“I have been a conservative Republican my entire life. But the Republican party as a whole has gotten so far out of touch with the American people,” says Bryan Brown, a 47-year-old Oregon resident. “I switched my registration so that I could vote for Sanders in the primary, but the day the primary is over I’m going to register as an Independent.”

Anger and alienation have turned conventional wisdom upside down in this presidential election. Self-styled outsider candidates like Donald Trump and Ben Carson have surged in the polls. And as Republican candidates debate their conservative credentials, support for Sanders shows how difficult it can be to pin down what exactly it means to be conservative.

“Once you get out of Washington ‘conservative’ can mean all sorts of different things. Voters are often left of center on some issues and right of center on others. So someone like Trump or Sanders who talks about themselves in a way that doesn’t fit into a pre-ordained box could be appealing to a lot of people,” says Chris Ellis, a political science professor at Bucknell University.

In some cases, longtime Republican voters who have decided to support Sanders, like MacMillan, are rethinking their political affiliation entirely. (“I’m inclined to say I might stay with the Democratic Party because the Republican Party has changed and it’s not the way it used to be,” MacMillan says.) Far from claiming to have experienced a political conversion, other Republicans argue that Sanders actually embodies conservative values.