President Trump has never missed an opportunity to take credit for a rally on Wall Street on his watch, and now that swagger is coming back to bite him as stock indexes slide‚ including the worst Christmas Eve plunge in history.

The market’s terrible December is creating a growing sense of economic anxiety for Americans, and political anxiety for Trump, at a time when he needs confidence in his administration.

The market is on pace for the worst December since the Great Depression, even as the underlying economy remains strong. Banking is stable. Unemployment is incredibly low. Consumer confidence is strong. Median incomes are at an all-time high. But Trump’s fate is the sum of all parts and he personally made the Dow, Nasdaq and S&P the barometers of his success.

Trump’s Treasury Secretary Steve Mnuchin added to the concern by convening the Plunge Protection Team, a working group designed to get regulators and economic leaders on the same page about financial markets. But many analysts argued that the move came too soon, and actually hastened negative market activity.

The chaos in the Trump administration isn’t helping matters. The president’s separations from his chief of staff and secretary of defense were needlessly destabilizing, as was his abrupt decision to shut the government down over “the wall,” cornering his Republican allies in Congress. Add to all that the needless economic turmoil caused by Trump’s trade wars and tariffs, and the year is ending terribly for him, and the markets are noticing.

Trump can’t lose the confidence of his base. No matter the scandal, Trump has persevered mostly because things are good in America right now. One friend, a supporter, often shrugs and tells me: “He’s a different kind of politician.” But overlaying economic uncertainty atop of the daily disorder that already makes him intolerable to about half the country will make it much harder for those who have given him many, many passes to keep giving more.

With Special Counsel Bob Mueller’s report looming, along with Democratic control of the House, it’s unlikely that Trump can lose economic confidence and keep his base of support.

Trump will keep trying to blame the market’s poor performance on the Fed chair that he appointed, or on Nancy Pelosi, or on the media. Days before November’s election, Trump tweeted: “If you want your stocks to go down, I strongly suggest voting Democrat.” But the markets had a huge rally the day after the midterms, suggesting investors were celebrating divided government.

One of the major areas of concern for Republicans after the midterms should be their dismal performance with the voters over 50, whose support was key to his upset of Hillary Clinton. But those older voters are acutely aware of the market’s highs and lows as they are more likely to invest in the market, to already be living off of it or relying on it in the near future. If they think Trump is bad for the market, they may conclude he’s bad for them.

President Trump is also going to try and make the Federal Reserve the boogeyman. Rising interest rates certainly have a lot more to do with market performance than John Kelly’s departure. But the threat that he would try to fire Fed Chairman Jay Powell—whom he appointed—is destabilizing in itself. Acting White House Chief of Staff Mick Mulvaney and Secretary Mnuchin had to try and calm investor nerves on that point, but jeopardizing the independence of the Fed would also cause more disruption. And anyway, most Americans don’t know who Jay Powell is.

Trump’s chief economic adviser Larry Kudlow once said: “I have long believed that stock markets are the best barometer of the health, wealth and security of a nation.” He must know that today’s stock-market message is not favorable for the president and should advise his boss to calm down, project stability for a few months if possible, and let congressional Republicans focus on a true middle-class economic agenda, rather than defending his ill-advised impulses.

Otherwise, Republican 2020 election outcomes will look like December’s market charts.