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In May, Donald Trump thought the Federal Reserve handled interest rates exactly right.

“Right now I am for low interest rates, and I think we keep them low,” he told CNBC.

Today, he said Fed chair Janet Yellen’s interest rate decisions proved she was “obviously not independent” from the White House and was, in fact, a partisan conspirator out to help Democrats.

“It's staying at zero because she's obviously political and she's doing what Obama wants her to do,” Trump told CNBC on Monday. “And I know that's not supposed to be the way it is, but that's why it's low.”

In an interview last week with Reuters, Trump said the low rates had created a "false economy," adding, "at some point the rates are going to have to change."

What changed between May and today? Nothing. The Fed has the same policy of low interest rates that Trump gushed over just four months ago. They last voted to raise rates in December 2015, the first time in nearly a decade, although there’s speculation among analysts that they could raise them this month.

Like a lot of Trump’s flip-flops, it’s not clear what prompted the shift. But it’s hard to reconcile Trump’s comments from springtime, where he warned of terrible economic consequences from an interest rate hike, with his comments today.

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Trump repeated his strong support for a low interest rate policy throughout his May interview with CNBC, warning that “one point more, even, is devastating” and that “we have to be very, very careful” about making changes as a result.

While he said he planned to replace Yellen when her term expired, he described her at that time as a kindred spirit on the issue.

“She is a low interest rate person, she has always been a low interest rate person, and I must be honest -- I am a low interest rate person,” Trump told CNBC on May 5. “If we raise interest rates and if the dollar starts getting too strong, we’re going to have very major problems.”

He gave Fortune a similar assessment in April, saying a rate increase would be “scary” for the economy.

“The best thing we have going for us is that interest rates are so low,” Trump said. “There are lots of good things that could be done that aren’t being done, amazingly.”

On Monday, those substantive arguments for low interest rates had disappeared in favor of wild accusations of shady behavior around the same course of action.

“She's keeping them artificially low" to boost Obama, he said. “Watch what's going to happen afterwards, it's a very serious problem. And I think it's very political. I think she's very political. And to a certain extent, I think she should be ashamed of herself.”

This isn’t the first time Trump has lurched erratically between extremes on the issue. He also accused Yellen of refusing to raise rates for political reasons last November.

“Janet Yellen should have raised the rates,” Trump told reporters. “She’s not doing it because the Obama administration and the president doesn’t want her to.”

The Fed voted to raise rates the next month.

Bumps in the economy tend to hurt the party in power, and partisans often grumble around election time that low interest rates are helping incumbents. Already, markets have been shaky this week as investors increasingly believe the Fed might announce a rate increase, which could slow growth in the short term in order to guard against inflation.

Whatever his motive, Trump’s comments drew a brush-back from Minneapolis Federal Reserve President Neel Kashkari, who is a Republican.

"Politics simply does not come up," Kashkari said on CNBC Monday. "We look at the economic data and ... everyone around the table is committed to achieving our dual mandate of employment and inflation.”