Michael Grunwald’s profile of Office of Management and Budget Director Mick Mulvaney for Politico starts with an extraordinary anecdote — seemingly sourced to Mulvaney himself — about how he tricked Donald Trump into violating his pledge to avoid proposing any cuts to Social Security.

According to Grunwald, Mulvaney — a very ideologically orthodox conservative who hates the idea of spending money on domestic social assistance programs — knew that Trump’s campaign promises were a problem for him. But he charged ahead anyway by bringing a big list of proposed cuts to a meeting at the Oval Office:

“Look, this is my idea on how to reform Social Security,” the former South Carolina congressman began. “No!” the president replied. “I told people we wouldn’t do that. What’s next?” “Well, here are some Medicare reforms,” Mulvaney said. “No!” Trump repeated. “I’m not doing that.” “OK, disability insurance.” This was a clever twist. Mulvaney was talking about the Social Security Disability Insurance program, which, as its full name indicates, is part of Social Security. But Americans don’t tend to think of it as Social Security, and its 11 million beneficiaries are not the senior citizens who tend to support Trump. “Tell me about that,” Trump replied. “It’s welfare,” Mulvaney said. “OK, we can fix welfare,” Trump declared.

Whether or not a given program constitutes “welfare” or not is essentially in the eye of the beholder. But Social Security Disability Insurance is definitely part of Social Security, which is why it’s called “Social Security Disability Insurance” and administered by the Social Security Administration. So when the Trump administration rolled out a budget that proposed large cuts to Social Security Disability Insurance, Vox wrote about how he was breaking his promise not to cut Social Security. The official White House line was that secretly Trump’s repeated pledges not to cut Social Security were really just pledges not to cut Social Security’s old age program.

But according to Mulvaney, it’s simpler than that. Trump broke his pledge because one of the most powerful people in the government duped him.

He used an abbreviated name when describing the program to Trump. When Trump asked a clarifying question, Mulvaney refused to provide all the relevant information. Those missing details might have helped lead the president to make a different decision, Mulvaney believed.

As extraordinary as that story is, two things about it are even more extraordinary:

Mulvaney appears to be comfortable openly bragging to the press about how he duped the president of the United States, even while he continues to serve as one of his senior advisors.

Nobody else in the budget process thought to check twice whether Trump really wanted to come out of the gate breaking a signature campaign promise and force Mulvaney to revisit this point.

It’s a heck of a way to run the government.