Swing state

In American presidential elections, each state is free to decide the method by which its electors to the Electoral College will be chosen. To increase its voting power in the Electoral College system, every state, with the exceptions of Maine and Nebraska, has adopted a winner-take-all system, where the candidate who wins the most popular votes in a state wins all of that state's electoral votes.[3] The expectation was that the candidates would look after the interests of the states with the most electoral votes. However, in practice, most voters tend not to change party allegiance from one election to the next, leading presidential candidates to concentrate their limited time and resources campaigning in those states that they believe they can swing towards them or stop states from swinging away from them, and not to spend time or resources in states they expect to win or lose. Because of the electoral system, the campaigns are less concerned with increasing a candidate's national popular vote, tending instead to concentrate on the popular vote only in those states which will provide the electoral votes it needs to win the election, and it is far from unheard of for a candidate to secure sufficient electoral votes while not having won the national popular vote.

In past electoral results, Republican candidates would have expected to easily win most of the mountain states and Great Plains, such as Idaho, Wyoming, the Dakotas, Montana, Utah, Kansas, Oklahoma, and Nebraska, most of the South, including Alabama, Mississippi, Louisiana, Arkansas, Tennessee, Kentucky, and South Carolina, as well as Alaska. Democrats usually take the Mid-Atlantic states, including New York, New Jersey, Maryland, and Delaware, along with New England, particularly Vermont, Massachusetts, Rhode Island, and Connecticut, the West Coast states of California, Oregon, Washington, along with Hawaii. They also are likely to win New Mexico and Illinois, based on recent election results.[4][5]

However, some states that consistently vote for one party at the presidential level occasionally elect a governor of the opposite party; this is currently the case in Massachusetts, Maryland, and Vermont, which all have Republican governors, as well as in Louisiana, Kentucky, and Kansas, which currently have Democratic governors. Even in presidential election years, voters may split presidential and gubernatorial tickets. In 2020, this occurred in Vermont and New Hampshire, which elected Republican governors even as Democrat Joe Biden won both states, while North Carolina elected a Democratic governor despite also voting for Republican Donald Trump.[6]

In Maine and Nebraska, the apportionment of electoral votes parallels that for U.S. senators and representatives. Two electoral votes go to the candidate who wins the plurality of the vote statewide, and a candidate gets an additional electoral vote for each congressional district in which they receive a plurality.[3] Both of these states have relatively few electoral votes – a total of 4 and 5, respectively. Despite their rules, each state has split its electoral votes twice – in 2008, when Nebraska gave four votes to Republican John McCain, and one to Democrat Barack Obama, and in 2020, when Nebraska gave four votes to Donald Trump and one to Joe Biden; in 2016 and 2020, Donald Trump won one vote in Maine, while Hillary Clinton and Joe Biden both were awarded three, respectively.[3][7]

States where the election has a close result become less meaningful in landslide elections. Instead, states which vote similarly to the national vote proportions are more likely to appear as the closest states. For example, the states in the 1984 election with the tightest results were Minnesota, and Massachusetts. A campaign strategy centered on them, however, would not have been meaningful in the Electoral College, as Democratic nominee Walter Mondale required victories in many more states than Massachusetts, Republican Ronald Reagan still would have won by a large margin.[8] Instead, the tipping-point state that year was Michigan, as it gave Reagan the decisive electoral vote. The difference in Michigan was nineteen percentage points, quite similar to Reagan's national margin of eighteen percent.[8] Michigan would have been more relevant to the election results had the election been closer.

Similarly, Barack Obama's narrow victory in Indiana in the 2008 election inaccurately portrays its status as a battleground. Obama lost Indiana by more than ten percentage points in the closer 2012 election, but triumphed anyway as Indiana's electoral votes were not directly needed for a coalition of 270 votes; the same scenario was with Missouri, where John McCain narrowly won by 4,000 votes in the 2008 election, but was won by Mitt Romney by nearly 10 points in 2012 election, indicating its GOP trend. Other lightly Republican leaning states such as North Carolina and Arizona were more plausible Democratic pick-ups in 2012.[9] In 2012, the states of North Carolina, Florida, Ohio, and Virginia were decided by a margin of less than five percent. However, none of them were considered the tipping-point state, as Romney would not have been able to defeat Obama even if he had emerged victorious in all of them. Interestingly, Virginia was most in-step with the rest of the country. Virginians voted for Obama by just under 4 points, almost the exact same as the nation.[9] Had the election come out closer, Romney's path to victory would probably have involved also winning Wisconsin, Nevada, New Hampshire, or Iowa, as these states had comparable margins to Colorado, and had been battlegrounds during the election.

As many mathematical analysts have noted, however, the state voting in a fashion most similar to that of the nation as a whole is not necessarily the tipping-point.[10] For example, if a candidate wins only a few states but does so by a wide margin, while the other candidate's victories are much closer, the popular vote would likely favor the former.[11][12] However, although the vast majority of the states leaned to the latter candidate in comparison to the entire country, many of them would end up having voted for the loser in greater numbers than did the tipping-point state.[13] The presidential election in 2016 was a notable example, as it featured one of the largest historical disparities between the Electoral College and popular vote.[14][15] Additionally, this "split" in votes was much larger in both directions than in previous elections, such as the 2000 election.[16] In that election, Vice President Al Gore won the popular vote by less than 1 percent, while incoming president George W. Bush won the Electoral College by only 5 votes.[16] In contrast, 2016 Democratic nominee Hillary Clinton won the popular vote by over 2 percentage points.[17][18] This meant that Donald Trump would have picked up New Hampshire, Nevada, and Minnesota if the popular vote had been tied, assuming a uniform shift among the battleground states.[19][20] On the other hand, Clinton would have had to win the popular vote by at least 3 points to win the Electoral College, as Trump, the Republican nominee, won the tipping-point state of Wisconsin by less than 1 percent.[21] In 2020, Joe Biden won the popular vote by over 4 percentage points but won the tipping point state of Pennsylvania by only 1 percent. This shows Donald Trump could win the election even if he lost the popular vote by over 3 percent and would have picked up Georgia, Arizona, and Wisconsin with a uniform shift among the states.

Swing states have generally changed over time. For instance, the swing states of Ohio, Connecticut, Indiana, New Jersey and New York were key to the outcome of the 1888 election.[22] Likewise, Illinois[23] and Texas were key to the outcome of the 1960 election, Florida and New Hampshire were key in deciding the 2000 election, and Ohio was important during the 2004 election. Ohio has gained its reputation as a regular swing state after 1980,[24][25] and did not vote against the winner from 1960 to 2020.[26] In fact, only three people have won the presidential election without winning Ohio since 1900: Franklin D. Roosevelt, John F. Kennedy, and Joe Biden. Areas considered battlegrounds in the 2020 election were Arizona, Florida, Georgia,[27] Iowa, Maine's 2nd congressional district, Michigan, Minnesota, Nebraska's 2nd congressional district, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania, Texas and Wisconsin,[28] with Florida, Michigan, Ohio, Pennsylvania, and Wisconsin constituting the "Big Five" most likely to decide the electoral college.[29] In the end, Joe Biden won Arizona, Georgia, Michigan, Minnesota, NE-02, Nevada, New Hampshire, Pennsylvania, and Wisconsin, while Donald Trump only won ME-02, Florida, Iowa, North Carolina, Ohio and Texas.

Campaign strategies are not universal in swing states. Statistical analytics website FiveThirtyEight notes that some swing states, such as New Hampshire, swing because they have many moderate, independent swing voters, and campaigning puts an emphasis on persuading voters. Contrasting this is Georgia, which is a swing state because it has large populations of Republican-leaning evangelical whites and Democratic-leaning Black voters and urban college-educated professionals, thus campaigns often concentrate on voter turnout.[30]

Presidential campaigns and pundits seek to keep track of the shifting electoral landscape. While swing states in past elections can be determined simply by looking at how close the vote was in each state, determining states likely to be swing states in future elections requires estimation and projection based on previous election results, opinion polling, political trends, recent developments since the previous election, and any strengths or weaknesses of the particular candidate involved. The swing-state "map" transforms between each election cycle, depending on the candidates and their policies, sometimes dramatically and sometimes subtly. For example, in the 2016 election, Hillary Clinton overperformed in educated, suburban states such as Virginia and Colorado compared to past Democratic candidates, while Donald J. Trump performed over standard Republican expectations in the Rust Belt, such as Michigan, Ohio, and Pennsylvania. In addition, gradual shifts can occur within states due to changes in demography, geography, or population patterns. For example, many currently Republican states, like Arkansas, Missouri, Tennessee, and West Virginia, had been battlegrounds as recently as 2004.[31] According to a pre-election 2016 analysis, the thirteen most competitive states were Wisconsin, Pennsylvania, New Hampshire, Minnesota, Arizona, Georgia, Virginia, Florida, Michigan, Nevada, Colorado, North Carolina, and Maine. Nebraska's 2nd congressional district was (and is still as of 2020) also considered competitive.[32] However, this projection was not specific to any particular election cycle, and assumed similar levels of support for both parties.[33]

Ten weeks before the 2020 presidential election, statistical analytics website FiveThirtyEight noted that the electoral map is "undergoing a series of changes", with some states moving rightward, other states moving leftward, and two states (Florida, until the 2020 election, and North Carolina) described as "perennial" swing states.[34][35] Likewise, an analysis of results of the 2018 midterms indicated that the "battleground states" are changing, with Colorado and Ohio becoming less competitive and more Democratic and Republican, respectively, while Georgia and Arizona were slowly turning into swing states.[36][37][38]

The electoral college encourages political campaigners to focus most of their efforts on courting swing states. States in which polling shows no clear favorite are usually targeted at a higher rate with campaign visits, television advertising, get out the vote efforts by party organizers and debates. According to Katrina vanden Heuvel, a journalist for The Nation, "four out of five" voters in the national election are "absolutely ignored".[39]

Since most states use a winner-takes-all arrangement, in which the candidate with the most votes in that state receives all of the state's electoral votes, there is a clear incentive to focus almost exclusively on only a few undecided states. In contrast, many states with large populations such as California, Texas and New York have in recent elections been considered "safe" for a particular party, and therefore not a priority for campaign visits and money. Meanwhile, twelve of the thirteen smallest states are thought of as safe for either party – only New Hampshire is regularly a swing state.[40] Additionally, campaigns stopped mounting nationwide electoral efforts in the last few months near/at the ends of the blowout 2008 election, but rather targeted only a handful of battlegrounds.[40]

This is a chart of swing states using the methodology of Nate Silver for determining tipping point states, but including the other states in close contention in recent elections, ranked by margin of victory.[41] In this method, states and DC are ordered by margin of victory, then tabulating which states were required to get to 270+ electoral votes in margin order. The tipping point state, and the next 10 states with close margins on each side, are shown as the swing states in retrospect, along with the "bias" which is the difference between the final margin in the tipping point state and final popular vote margin. Note that this takes into account inherent electoral college advantages; for example, Michigan was the closest state in 2016 by end result, and Nevada was the closest state to the national popular vote result, but the tipping points that most mattered for assembling a 270 electoral vote coalition were Wisconsin and Pennsylvania.[41]

• Bellwether
• Blue wall (politics)
• Marginal seat
• Missouri bellwether
• Purple America
• Red states and blue states

• The Critical 2012 Swing States
• Battleground States 2008 via the Washington Post
• Swing State Ohio Documentary
• Swing State feature documentary project
• Guide to the 2004 swing states from Slate
• Battleground states from Democracy in Action site hosted by George Washington University
• How close were Presidential Elections? Influential States – Michael Sheppard
• The Bush campaign memo detailing its look at the swing states (PDF file)