Bob Corker, the Senate’s lone Republican holdout on the GOP tax-reform bill, flipped his vote to yes after the legislation was finalized on Friday. “After great thought and consideration, I believe that this once-in-a-generation opportunity to make U.S. businesses domestically more productive and internationally more competitive is one we should not miss,” Corker, a commercial real estate magnate who’s retiring from the Senate at the end of next year, said in a statement. A day later, the International Business Times revealed that a last-minute provision in the bill, granting a major tax deduction to owners of real estate partnerships, would benefit Corker by about $1.2 million per year.

Corker, who is already under federal investigation for alleged insider trading involving a real-estate firm, spent the weekend making a series of less-than-convincing statements justifying his switch. He first told IBT that he hadn’t read the bill. Then he wrote an angry letter to Senate leaders questioning how this provision got into the bill. As #CorkerKickback trended on Twitter, the senator also claimed that the language was part of the House version of the legislation. Experts rejected that. “This new language can’t be found in either the House-passed or Senate-passed bills,” Matt Gardner of the Institute on Taxation and Economic Policy told IBT.

Corker originally opposed the tax bill because of its impact on the federal budget deficit.

My statement on the tax reform legislation: pic.twitter.com/LdTQRezdlO — Senator Bob Corker (@SenBobCorker) December 1, 2017

And yet, the bill being voted on this week could still “deepen the debt burden on future generations,” as Corker defines it. So why did he change his vote, if he wasn’t influenced by the potential for personal enrichment?

This episode represents a marked shift in how self-interest plays out in Washington, even compared with a few years ago. During the health care debate from 2009 to 2010, Senator Ben Nelson was savaged over the “Cornhusker kickback,” which would have subsidized Nebraska’s share of payments for expanding Medicaid; the provision was pulled from the final legislation. Similar deals increased Medicaid spending in Louisiana to win Senator Mary Landrieu’s vote and gave a $100 million grant for a public hospital in Connecticut to win Senator Chris Dodd’s. But at least those measures were intended to benefit residents of particular states—some of their poorest citizens, in fact. In the case of Corker, he gets the benefit personally.