The Short Answer: Plurality Rules
No, Illinois does not require a candidate to win a majority (more than 50%) of the vote to be elected to a federal office in a general election. Instead, Illinois uses a 'plurality' voting system. This method, also known as 'first-past-the-post', means that the candidate who receives the most votes wins, even if they don't secure an outright majority. For example, if a candidate in a three-way race gets 45% of the vote, while their opponents get 40% and 15%, the candidate with 45% is declared the winner. This applies to all single-winner federal races in the state.
How This Applies to Federal Elections
This plurality rule is consistent across all major federal elections held in Illinois. This includes the statewide races for the U.S. Senate and the district-by-district races for the U.S. House
of Representatives. While the presidential election is technically decided by the Electoral College, Illinois awards all of its electoral votes to the candidate who wins the state's popular vote, again based on a plurality. The winner of the popular vote in Illinois gets all the electoral votes, regardless of whether their margin of victory is 20 points or less than a single percentage point. Illinois law specifies that for both primary and general elections, the winner is the person with the highest vote total.
Why No Runoffs in Illinois?
Some states, like Georgia and Louisiana, use a different system for some or all of their elections, requiring a runoff election if no candidate wins a majority in the initial vote. These two-round systems are designed to ensure the eventual winner has the support of more than half of the voters. Illinois, along with the majority of U.S. states, has historically favored the simplicity and finality of the plurality system for its general elections. This avoids the cost and potential for lower turnout associated with a second round of voting. The system is deeply rooted in the Anglo-American tradition of 'first-past-the-post' elections and has remained the standard for state and federal contests in Illinois.
The Impact of Third-Party Candidates
One of the most significant consequences of a plurality system is the role of third-party or independent candidates. In a tight race, a third candidate can draw votes away from one of the major party candidates, potentially changing the outcome of the election. This is often called the 'spoiler effect'. For instance, a candidate could win with just 38% of the vote if two other candidates split the remaining 62%. Critics of the plurality system argue that it can lead to winners who are not supported by a majority of voters and discourages people from voting for third-party candidates out of fear of 'wasting' their vote.
Is Change on the Horizon?
While the plurality system is firmly in place for federal and state elections, there is a growing conversation around electoral reform in Illinois. Some local municipalities have explored or even passed referendums to adopt Ranked-Choice Voting (RCV) for local elections. In an RCV system, voters rank candidates in order of preference. If no candidate has a majority, the last-place candidate is eliminated, and their votes are redistributed to their voters' next choice until one candidate surpasses 50%. However, implementing these systems has faced legal and legislative hurdles, and as of late 2026, state law does not provide for ranked-choice voting in statewide or federal contests. For the foreseeable future, plurality remains the law of the land for federal offices in Illinois.
