During Thursday night's GOP debate, Donald Trump bragged about how he deliberately gave money to politicians so that he could later get favors from them. He even said that he used donations to get Hillary Clinton to go to his wedding — that his giving left her with "no choice."

Update: Coverage of CNN's Republican debate.

It was a bizarre, but effective, diagnosis of the deep corruption in American politics. Reformers tend to present themselves as blameless. Trump is presenting himself as someone who has so mastered the corruption of American politics that he can be trusted to resist it. Here's the exchange:

Q: You've also supported a host of other liberal policies, you've also donated to several Democratic candidates, Hillary Clinton included, Nancy Pelosi. You explained away those donations saying you did that to get business related favors. And you said recently, quote, when you give, they do whatever the hell you want them to do. TRUMP: You better believe it... I will tell you that our system is broken. I gave to many people. Before this, before two months ago, I was a businessman. I give to everybody. When they call, I give. And you know what? When I need something from them, two years later, three years later, I call them. They are there for me. And that's a broken system. Q: So what did you get from Hillary Clinton and Nancy Pelosi? TRUMP: I'll tell you what. With Hillary Clinton, I said, be at my wedding and she came to my wedding. You know why? She had no choice! Because I gave.

Here, indeed, is a picture of the Clintons at Trump's 2005 wedding:

Trump's analysis of how money influences politics isn't about straight bribery. It's about building a long-term relationship in which each side does favors for the other. He gives to politicians, and then, he says, "When I need something from them, two years later, three years later, I call them."

Something Trump identifies that doesn't always get mentioned is the way transactional politics transcend partisanship and ideology. Trump gave to Democrats and he gave to Republicans. He didn't care what they believed. He cared what they could do for him. He wasn't supporting them — he was buying them, and that's completely different.

It's common for politicians to say that Washington is corrupt and broken. But, generally, they tend to portray themselves as blameless. It's always everyone else who's corrupt.

But as Ezra Klein wrote, Donald Trump is a man without shame. He sees no problem in admitting that he tried to buy politicians to benefit himself and his company. And since he so boldly admits that he gave money to get favors out of politicians, his diagnosis of the system as corrupt and broken is more credible. (It also serves as a handy excuse for why he gave to Democrats — in his telling, they're corrupt and he wanted to buy them.)

One of the main themes I've heard from Trump supporters explaining why they support him is their belief that he "can't be bought." And weirdly enough, his frankness about how he himself has tried to buy others helps make this point.

Watch: Donald Trump on becoming a Republican