Just as much as, if not more than, Sanders, Trump has made political bribery a core issue in his campaign. From the first Republican Primary debate when he called out every other Republican candidate as being bought off to the last Presidential debate we just saw when he called out Hillary for being beholden to the donor class, he's been consistent in his critique of money in politics.
The point isn't that Trump is secretly a progressive Democrat, it's that due to certain historical and socio-economic factors, the traditional Republican-Democrat paradigm is becoming increasingly irrelevant. So whereas someone looking through that outdated lens would see Trump on the far right, Clinton in the middle, and Sanders on the far left, a more up-to-date analysis would show that Trump and Sanders are actually tapping into similar underlying factors to paint their political picture. If you were to do a word-match from all of the candidates rallies and speeches, you'd find a closer correlation between Trump and Sanders than Clinton and Sanders. Words like "rigged", "corrupt", "special interests", "donors", "NAFTA", "TPP" show up frequently in both Trump and Sanders' wheelhouse. And those are the words both of their supporters most latch on to. Don't get it twisted, Sanders campaign wasn't some big corporate diversity pitch. That was Clinton's, which is why she can so easily paint an oppositional narrative to Trump. The protests Sanders' supporters launched on the floor of the DNC wasn't about getting more women's representation in media or using politically correct terminology about immigration and islam, it was criticizing damaging trade deals and the war machine. On which side of those issues is Trump on? That's right. Ultimately, Sanders was talking about material changes to the underlying structure of American society, which is what Trump is talking about, which is why he's been namechecking Bernie every time he opens his mouth over the past few months.
