Every four years, voters will see a handful of partisan apostates throw their support behind the other party's nominee -- Georgia's Zell Miller, for example, delivered an unfortunate keynote address at the Republican convention in 2004 -- and these isolated voices are often exaggerated to make it appear as if White House hopefuls enjoy broad, bipartisan support.
But in 2020, Joe Biden's Republican support is qualitatively different.
At last week's Democratic convention, for example, Americans heard from some prominent GOP voices -- former Ohio Gov. John Kasich (R), former Secretary of State Colin Powell, former Rep. Susan Molinari (R-N.Y.), et al. -- throw their support behind the Democratic ticket. The day after Powell spoke, several dozen Republican national security officials -- from the Reagan, Bush/Quayle, and Bush/Cheney administrations -- also endorsed Biden.
Today, as Trump's Republican nominating convention gets underway, the list of Biden's GOP backers is growing in unexpected ways.
More than two-dozen former Republican members of Congress, including ex-Sen. Jeff Flake of Arizona, endorsed Joe Biden for president on Monday, hours ahead of the Republican National Convention. Biden's presidential campaign announced the list of endorsements in a press release Monday morning.
The full list includes senators and representatives, from blue states and red states, including relative moderates like Pennsylvania's Charlie Dent and genuine conservatives like Jeff Flake. Also on the list is former Sen. John Warner (R-Va.), the former chairman of the Senate Armed Services Committee, and a man who helped steer GOP foreign policy for many years.
In the not-too-distant past, the idea that Republican voices like these would reject the re-election bid of their own party's president, and publicly endorse a Democratic rival, would've seemed outlandish. And yet, here we are.
It's easy to assume that the electoral impact of developments like these will be modest. Trump's intra-party backing is relatively strong, and many far-right voters, if they hear about these GOP Biden backers at all, will simply assume they're a bunch of centrist RINOs who deserve to be ignored.
But let's not overlook another group of voters: traditional Republicans whose support for their party is soft. They reluctantly backed Trump in 2016, largely because of their contempt for Hillary Clinton, and every day since, they've grown weary of their president's tweets, failures, and scandals.
These voters aren't satisfied with the status quo, and while they're reluctant to back a Democratic ticket, they're open to change. This is a constituency basically waiting for allies to tell them it's OK to choose Biden over Trump.
And for this contingent, a whole lot of prominent Republican voters are now encouraging them to do exactly that.