How Senate Vacancies Are Filled: State By State Rules

Table Of Contents

The short answer: In 43 states, the governor appoints a temporary senator when a seat becomes vacant. In 4 states, Kentucky, North Dakota, Rhode Island and Wisconsin, the seat stays empty until voters fill it in a special election. In 3 states, Connecticut, Louisiana and Texas, the governor can appoint only under limited conditions. Ten states require the governor to pick someone from the departed senator’s party, and in Kansas and Utah, the governor must choose from a shortlist of three names they did not write. How long the temporary senator serves, a few months or nearly two years, depends entirely on which state’s rulebook applies.

That paragraph is the summary. Everything below is detailed: the full 50-state table, the reasoning behind each model, the scandals these rules have produced, and the moments when a single vacancy rule changed control of the United States Senate.

Why America Has 50 Different Rulebooks

Until 1913, senators were not elected by voters at all — state legislatures chose them. The system produced two chronic problems: deadlocked legislatures that left Senate seats empty for months or years (Delaware once went four years with only one senator), and outright bribery, as candidates found it cheaper to buy a few dozen legislators than to win a statewide campaign.

The 17th Amendment fixed this by establishing direct election. However, its vacancy clause was a compromise. It requires the governor to call an election to fill an empty seat, while permitting each state legislature to authorize the governor “to make temporary appointments until the people fill the vacancies by election.”

Two words in that clause, “may” and “as the legislature may direct”, created the patchwork we have today. Congress never added a federal deadline, so each state decides for itself whether its governor has appointment power and how quickly the election must be held. More than 200 senators have entered the chamber by appointment since 1913, meaning a meaningful share of American legislation has been shaped by people no one voted for.

The Four Models, And Where Your State Fits

Model 1: Appoint now, elect at the next general election (35 states): The appointee serves until the next regularly scheduled statewide general election, which can be almost two years away if the timing is unlucky. This is the low-cost option, with no stand-alone election to fund, and the one that gives governors the most power.
States: Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, Utah, Virginia, West Virginia, Wyoming.
Model 2: Appoint now, but hold a fast special election (8 states): An interim appointment fills the gap, but a stand-alone special election must be held on an accelerated timeline, typically within 80 to 160 days. The appointee is a placeholder, not a power.
States: Alabama, Alaska, Massachusetts, Mississippi, Oklahoma, Oregon, Vermont, Washington.
Model 3: No appointment, the seat stays empty (4 states): Kentucky, North Dakota, Rhode Island and Wisconsin prohibit gubernatorial appointments entirely. The state operates with one senator until a special election concludes.
Model 4: Conditional appointment (3 states): Connecticut, Louisiana, and Texas allow appointments only in narrow circumstances; for example, Connecticut permits one only near the very end of a term, and even then, it must survive a two-thirds confirmation vote in both chambers of the legislature.
The extra layer: party locks and shortlists: Ten states, Arizona, Hawaii, Kansas, Maryland, Montana, Nevada, North Carolina, Utah, West Virginia and Wyoming, require the appointee to belong to the same party as the senator who left. Kansas and Utah additionally strip the governor of free choice: a legislative committee hands over three names, and the governor must pick one. Oregon’s 2025 law added a same-party requirement too, along with a rule found nowhere else so explicitly, the governor may not appoint themselves.

The Complete 50-State Table

Compiled from the National Conference of State Legislatures (updated March 2026), the Congressional Research Service, and state election codes. Two recent changes worth flagging, because most articles online still have them wrong: Kentucky abolished its governor’s appointment power in 2024, and Oregon restored its governor’s appointment power in 2025. Any article that says “five states prohibit appointments” predates those changes.

State	Can the governor appoint?	Same party required?	When is the seat filled by election?
Alabama	Yes	No	Expedited special election, ordered “forthwith” if more than 4 months remain before a general election
Alaska	Yes	No	Special primary within 60–90 days of the vacancy; special election within 60 days after that
Arizona	Yes	Yes	Next general election (second one if the vacancy falls within 150 days of the primary)
Arkansas	Yes	No	Next general election if 4+ months away; otherwise the following one
California	Yes	No	Next November election (second one if the vacancy falls within 148 days of the primary)
Colorado	Yes	No	Next general election
Connecticut	Conditional	—	Special election ~150 days after the governor’s call; appointment allowed only near the end of a term, and it needs a two-thirds vote of both legislative chambers
Delaware	Yes	No	Next general election
Florida	Yes	No	Next general election
Georgia	Yes	No	Next November general election at least 40 days after the vacancy
Hawaii	Yes	Yes	Next November election (second one if the vacancy falls within 21 days of the primary)
Idaho	Yes	No	Next general election (second one if the vacancy is within 30 days of it)
Illinois	Yes	No	Next general election
Indiana	Yes	No	Next general election (second one if the vacancy falls after candidate certification, 74 days out)
Iowa	Yes	No	Next general election
Kansas	Yes	Yes	Next general election; a 12-member legislative committee gives the governor a list of three names to choose from
Kentucky	No	—	Special election only; timing not fixed in statute (appointment power removed in 2024)
Louisiana	Conditional	—	Special election on dates set by law if more than a year remains in the term; a temporary appointment bridges the gap. If a year or less remains, the appointee serves until the next regular election
Maine	Yes	No	Next general election (second one if the vacancy falls within 60 days of the primary)
Maryland	Yes	Yes	Next regular statewide election, if the vacancy occurs at least 21 days before the candidate-filing deadline
Massachusetts	Yes	No	Stand-alone special election 145–160 days after the vacancy
Michigan	Yes	No	Next November election that is more than 120 days after the vacancy
Minnesota	Yes	No	Next November election (second one if the vacancy falls within 11 weeks of the primary)
Mississippi	Yes	No	Special election within 115 days of official notice, or at that year’s general election if one is scheduled
Missouri	Yes	No	Next general election
Montana	Yes	Yes	Next general election
Nebraska	Yes	No	Next general election if the vacancy occurs by Aug. 1 of that year; otherwise the following one
Nevada	Yes	Yes	Next general election
New Hampshire	Yes	No	Next general election
New Jersey	Yes	No	Next general election if more than 70 days away; the governor may also call an earlier special election
New Mexico	Yes	No	Next general election at least 30 days after the vacancy
New York	Yes	No	Next November election (second one if the vacancy falls within 59 days of the primary)
North Carolina	Yes	Yes	First general assembly election more than 60 days after the vacancy
North Dakota	No	—	Special election within 95 days; if less than 95 days remain in the term, the seat simply stays vacant
Ohio	Yes	No	Next regular state election more than 180 days after the vacancy
Oklahoma	Yes	No*	Special election aligned with the next available regular primary, runoff and general election dates
Oregon	Yes (within 30 days)	Yes**	Stand-alone special election 80–150 days after the vacancy (appointment power restored in 2025)
Pennsylvania	Yes	No	Next general or municipal election at least 90 days after the vacancy
Rhode Island	No	—	Special election as early as legally possible; held with the general election if the vacancy occurs July–October of an even year
South Carolina	Yes	No	Next general election (second one if the vacancy occurs within 100 days of it)
South Dakota	Yes	No	Next general election
Tennessee	Yes	No	Next general election
Texas	Conditional	—	Special election on the first uniform election date at least 36 days after it is ordered; the governor appoints a temporary senator only if Congress is or will be in session
Utah	Yes	Yes	Election timed to coincide with a municipal or general election; the governor picks from three names submitted by the legislature
Vermont	Yes	No	Special election within six months, or at the general election if the vacancy occurs within six months of it
Virginia	Yes	No	Next November election (second one if the vacancy falls within 120 days of it)
Washington	Yes	No	Special election at least 80 days after the vacancy, or at the general election if the vacancy occurs within 8 months of it
West Virginia	Yes	Yes	General election, with a special primary added if the vacancy falls between the primary and general windows
Wisconsin	No	—	Special election 62–77 days after the order, or at the regular elections if the vacancy occurs in the April–May window of an even year
Wyoming	Yes	Yes	Next general election

Oklahoma’s statutes have attached same-party and other conditions to appointments in certain scenarios since 2021; check the current statute for the specific situation.
Oregon’s 2025 law requires the appointee to share the departed senator’s party and bars the governor from appointing themselves.

When Vacancy Rules Changed History

The table looks bureaucratic. The consequences have not been.

Illinois, 2008: A Senate Seat For Sale

When Barack Obama won the presidency, his Illinois Senate seat fell to Governor Rod Blagojevich to fill, a Model 1 appointment with no restrictions. Federal wiretaps caught Blagojevich treating the appointment as an asset to sell, musing about what he could extract in exchange for the seat. He was arrested, impeached, removed from office and eventually imprisoned. The scandal triggered a national debate about whether any single politician should hold that much unchecked power, and it is a large part of why states like Kansas, Utah and Oregon have since fenced in their governors with shortlists and party locks.

Massachusetts, 2004–2010: The Rule That Flipped Twice And Broke A Supermajority

In 2004, the Democratic legislature stripped Republican Governor Mitt Romney of appointment power, fearing he would replace Senator John Kerry with a Republican if Kerry won the presidency. In 2009, with a Democratic governor in office and Senator Ted Kennedy dying during the healthcare fight, the same legislature reversed itself. It restored appointments so the seat would not sit empty. The appointed placeholder, Paul Kirk, briefly preserved the Democrats’ 60-vote, filibuster-proof majority. Then the special election arrived, and Republican Scott Brown won Kennedy’s seat, ending the supermajority and forcing Democrats to pass the Affordable Care Act through a narrower procedural path. A few episodes make it clear that vacancy mechanics are not paperwork; they are power.

Georgia, 1922: A One Day Senator And A Broken Barrier

When Senator Thomas Watson died, Georgia’s governor appointed 87-year-old Rebecca Latimer Felton, making her the first woman ever to serve in the United States Senate. She served roughly 24 hours before her elected successor took over, a symbolic appointment, but one that only the appointment mechanism made possible.

The Modern Routine

Appointments now happen almost every Congress. In 2023 alone, Nebraska’s governor appointed former governor Pete Ricketts after Ben Sasse resigned to become a university president, and California’s governor appointed Laphonza Butler after Dianne Feinstein died in office. Each appointment quietly shifts committee seats, floor votes and, in a closely divided Senate, potentially the majority itself.

Do Appointed Senators Keep Their Seats?

Mostly, no. Historical reviews of the 200-plus appointed senators show a consistent pattern: a large share never run for the seat at all (many are deliberately chosen as caretakers who promise not to), and of those who do run, a substantial portion lose. An appointment gives a candidate incumbency on paper, but not the things that usually make incumbency powerful: a statewide victory, a campaign organization, and a mandate. Voters seem to treat appointees as auditioners rather than incumbents.

Some exceptions turned an appointment into a long career, but the base rate is a warning to any governor who imagines they are anointing the next long-serving senator. More often, they are choosing a temp.

A Worked Example: South Carolina, 2026

The July 2026 death of Senator Lindsey Graham shows several of these rules operating at once — and shows why one vacancy can trigger two separate legal processes.

South Carolina is a Model 1 state with no party restriction, so Governor Henry McMaster appoints a temporary senator to serve out the remainder of Graham’s term, which ends in January 2027. That is process one.

Process two exists because Graham had already won his party’s primary for that November’s election. His death left a hole on the ballot, not just in the Senate, so state law triggered an expedited special primary (filing window within days, primary election in August, runoff two weeks later if needed) to choose a new nominee, who will face the Democratic nominee in November as originally scheduled.

The appointee and the eventual nominee can be the same person, and governors know an appointment functions as a head start, but nothing requires it.

(Note for future readers: this section uses the 2026 South Carolina vacancy as its example. The mechanics described apply to any South Carolina Senate vacancy.)

Why These Rules Keep Changing, And Why More Changes Are Coming

Vacancy statutes are rewritten for one reason: someone in power looks at the current rule and dislikes whom it empowers.

Kentucky’s 2024 change fit the pattern exactly: a Republican legislature removing appointment power from a Democratic governor, over his veto, while the state’s Senate seats were held by Republicans (including Mitch McConnell). Massachusetts flipped its rule twice in five years, in opposite directions, both times for immediate partisan advantage. Oregon moved the other way in 2025, restoring appointments but binding them with a same-party rule and a fast election clock, an attempt to get continuity of representation without the Blagojevich risk.

The structural pressure is permanent: at any given moment, roughly a quarter of governors belong to a different party than at least one of their state’s senators. Every one of those pairings is a live incentive for a legislature to rewrite the rule, before a vacancy makes it matter.

Frequently Asked Questions

What happens when a US senator dies in office?

The seat becomes vacant immediately. What happens next depends on state law: in 43 states, the governor appoints a temporary senator; in Kentucky, North Dakota, Rhode Island, and Wisconsin, the seat remains vacant until a special election is held; in Connecticut, Louisiana, and Texas, an appointment is possible only in limited circumstances.

How long does an appointed senator serve?

Until an elected successor is sworn in, not automatically until the term ends, in the next general election, states can be a few years away; in fast special-election states, it is usually a few months.

Does the replacement have to be from the same party?

Only in Arizona, Hawaii, Kansas, Maryland, Montana, Nevada, North Carolina, Utah, West Virginia, Wyoming, and Oregon under its 2025 law. Everywhere else, the governor may appoint anyone meeting the constitutional requirements.

What are the constitutional requirements to be a senator?

At least 30 years old, a US citizen for at least nine years, and a resident of the state at the time of election or appointment. That is the complete federal list; states cannot add qualifications.

Can a governor appoint themselves to the Senate?

Nothing in the Constitution prevents it, and it has happened historically (usually by resigning as governor so the successor makes the appointment, though a few governors have done it directly). Oregon’s 2025 law explicitly forbids it, the only state to spell that out so plainly.

Can the appointed senator run in the special election?

Yes, in every state, and the appointment is widely understood as an electoral head start, name recognition, incumbency framing, and a Senate office. History suggests the head start is smaller than it looks: most appointed senators do not go on to win the seat.

Why do some states leave the seat vacant instead of appointing someone?

In principle, only voters should choose a senator. The cost is that the state loses half its Senate representation, every committee assignment, every floor vote, for the weeks or months it takes to hold the special election.

Is the House of Representatives the same?

No. The Constitution requires every House vacancy to be filled by a special election. No House member has ever been appointed, which is why a House seat can remain vacant for months, while a Senate seat in most states is filled within days.

Who has the power to change these rules?

Each state legislature, under the 17th Amendment. Congress has occasionally debated a uniform national standard, especially after the Blagojevich scandal, but no proposal has ever advanced out of committee.

Has a vacancy ever changed which party controls the Senate?

Appointments and special elections have repeatedly shifted the working majority. The clearest modern example is Massachusetts in 2010, when a special election for a vacant seat ended the Democrats’ 60-vote supermajority mid-legislative-fight.