Ronald Reagan, the godfather of the modern Republican Party, was once a Democrat. In switching his allegiance, he said, “I didn’t leave the Democratic Party. The Democratic Party left me.”

For millions of Americans who see life in starkly partisan terms, it’s hard to imagine changing political teams. But both the “never Trump” Republicans and Bernie Sanders’ supporters’ enthusiasm for “democratic socialism” shows that what makes up the terms “Democrat” or “Republican” is flexible. 

But just how flexible, and what determines this bend? 

Marquette University Political Science Professor Julia Azari says American politics today is about “strong partisanship and weak parties.”

“The party doesn’t have much sort of apparatus to spread out the base of power. So the president sort of de facto becomes the party.” 

This explains how a political novice like Donald Trump went from reality TV star to the definer of all things Republican in just four years. But this singular power to infuse a party with new meaning is, itself, somewhat new. Azari provides some historical perspective.

 “So 19th century presidents were really dependent on local and state parties, and that’s how they won office. It’s like, no one really cared if you were whoever the presidential nominee was—what you said. What they cared about was their local party leader.”

These local leaders were the quintessential backroom bosses who did what they thought was “good for the party.” And what they thought was good ended up being what it meant to be a Republican or a Democrat. 

But times have changed in the past sixty years. 

Presidents and presidential candidates now tap into the appeal of heightened partisanship. And this enables candidates to bend their party to their way of thinking they prefer as candidates—even if that means sharp changes in policy and priorities. This is what happens in a two-party system, says Hamilton County Republican Party Chair Alex Triantafilou. 

“You know, in European countries, for instance, they have multiple political parties.  Here we stuff everyone into two groups and it’s hard.” 

Triantafilou agrees: the presidential candidates have a lot of sway in making the parties in their own image. But, he says local voters are fine with this set-up of coalition building that happens during the primaries. 

“We’ve got these coalitions. You know, we form our coalitions before the election by picking a nominee, and the nominees, especially as we stand here today, couldn’t see two more disparate people than Mitt Romney and Donald Trump, right?” 

And local party leaders act like boosters, says Cuyahoga County Democratic Party Chair and County Council Member, Shontel Brown.

“I have been called ‘the cheerleader’ if you will.”

But Brown also sees room for influence when it comes to what defines her party nationally.

“I have a unique position to keep people enthusiastic about the process, about politics, about the things that are happening. But I also have the duty and responsibility as the chair to be a voice to let the higher ups know ‘look these are some of the frustrations that are being expressed to me at the local level’.’’

For some, like Reagan questioning the Democratic Party of his era, the changes presidential candidates bring might be too much for people to tolerate. But most local voters and party leaders seem content to roll with the shifts and support their weak parties through their strong partisanship.