So we wondered: Could coming from a swing state boost a candidate’s chances of winning?
Polls show almost none of these Republicans leads Hillary Clinton in a head-to-head matchup today in their home state, but history tells a different story: presidential candidates consistently get a medium-size bump in their home states -- 3.61 percentage points on average in elections through 2008. Accounting for 2012, it's 3.5 points.
How can one determine whether a candidate got a home-state bump? Political scientists Christopher Devine and Kyle Kopko employed a surprisingly simple approach in a 2013 article in the journal Presidential Studies Quarterly. They compares how a candidate performed in their home state and nationally with their party’s average performance in the past five elections. If their national vote mirrored recent elections but their home state vote beat the 5-year average, they had a five-point home state advantage. (Written out, this = [state performance – 5 year party average] – [national performance – 5 year party average]).
Almost three-quarters of presidential candidates have received a home-state bump, and in 11 elections those advantages proved decisive in swinging states in their favorite sons’ direction, according to Devine and Kopko.
And that home-state bump could indeed make a pretty sizable difference come 2016. A typical 3.5-point bump would push Rubio or Bush above the 50 percent mark when compared to Republican candidates’ 49.5 percent average in the last five cycles. The same home state advantage would also be enough for Kasich to flip Ohio compared to Republicans' 49.1 percent average in recent elections. Wisconsin would be a bigger lift for a home-state edge to matter, but a typical 3.5-point edge would barely be enough to swing the Badger State for Walker. Other Republican hopefuls come from states where a typical home-state boost would not be enough to change the outcome (i.e. Chris Christie in New Jersey, Bobby Jindal in Louisiana, etc.).
Devine and Kopko found evidence that home state advantage is driven primarily by boosting turnout of a candidate’s supporters, rather than changing minds of those who already vote.
Now, there’s a gigantic caveat to the fascinating home-state advantage: It has never changed the outcome of a presidential race. This is because the Electoral College result is rarely close enough for an individual state to be decisive. The interactive chart below shows how this applies to 2016, with electoral data from Dave Leip's excellent Atlas of U.S. Presidential Elections.
Florida is a good example of the difficulty of a home-state advantage swinging an election. Despite its massive 29 electoral votes -- by far the biggest swing state -- just six of 40 elections since 1856 have been decided by a margin of that size or smaller. Divide that by two, since swinging Florida would only matter if the home-state candidate was trailing, and there’s a 7 percent chance a Florida-sized swing will matter.
Put together the chance of a home-state swing and the likelihood of it being decisive, and there’s a 5 percent chance a Florida home-state advantage for Bush/Rubio would swing the presidency in 2016. That dips to 4 percent for Ohio and 2 percent for Wisconsin. This estimate is rough and might be an underestimate, since two of the closest four elections have occurred recently. But even if we look at competitiveness of six elections since 1992, the chance of a Florida or Ohio home state bump swinging the presidency rises to 11 percent -- a one in nine shot.
Another reason to be skeptical is looking at the candidates whose home-state advantage was decisive in winning the state. Only one – Benjamin Harrison – actually became president, while many others got trounced. Here’s a comprehensive rundown of how those “wins” played out.
Elections where a candidate’s home-state advantage swung a state, but not the presidency
1888 Benjamin Harrison (R) – This was the closest a home state swing ever came to being decisive. Harrison’s home-state advantage swung Indiana’s 15 electoral votes, but they were icing on the cake – without the state, he would have still won a 218 electoral vote majority of the nation’s 401 electors.
1896 William Jennings Bryan (D) –Despite winning Nebraska, Bryan still lost to William McKinley by 95 electoral votes.
1908 Bryan (again)– Nebraskans were loyal to Bryan once again, but this round was a 321-162 knockout against William Howard Taft.
1940 Wendell Willkie (R) – Willkie won Indiana, but Roosevelt trounced him almost everywhere else in a 449-electoral-vote rout.
1948 Thomas Dewey (R) – Dewey did defeat Truman in his home state, he lost by 114 electoral votes in the biggest polling fail ever.
1960 Richard Nixon (R) – Nixon barely won California with the help of a small, 1.3-point home state advantage, but he still lost by 84 electoral votes.
1964 Barry Goldwater (R) – Goldwater had friends in Arizona, but not many elsewhere. He won just five other states.
1976 Gerald Ford (R) – Michigan swung for Ford but he still lost to Jimmy Carter by 57 electoral votes.
1980 Jimmy Carter (D) – Almost as lonely. Georgia was one of six states Jimmy Carter won.
1984 Walter Mondale (D) – So lonely. Minnesota was the only state Mondale won against Ronald Reagan. Ouch.
1992 George H.W. Bush (R)– Needed four more Texases. Bush was still 102 electoral votes short of the magic 270. His ‘advantage’ in Texas was losing less ground compared with recent Republicans than in other states.
Peyton M. Craighill contributed to this report.