President Trump has kept an almost obsessive watch on the stock market as it has lurched lower in recent weeks, tuning in to Fox Business and checking in with Lou Dobbs, a host on the network.

The president has complained to aides about how unfair it is that he is blamed for the market’s slide and for growing unease about an economic slowdown in the months to come, say current and former officials who spoke on the condition of anonymity because they were not authorized to speak publicly.

And he has needled Federal Reserve Chairman Jerome H. Powell about the pace at which the central bank has raised short-term interest rates.

The lower the market drops, the more the president worries that he is losing his most potent argument for reelection, several of the officials said.

The Dow Jones industrial average sank to the lowest point of the year Thursday, shedding nearly 500 points after Trump repeated threats to shut down part of the U.S. government if Congress doesn’t give him $5 billion for a border wall.

Watch more!

“Any measure that funds the government has to include border security,” Trump said as the market tumbled.

Unless a miracle “Santa Claus rally” emerges, this is going to be the worst year for U.S. stocks since 2008.

Since the 2016 election, Trump has pointed to market gains as proof that his economic policies are working and that the country is thriving under his leadership. Now a favored talking point is crumbling.

Before the market downturn, Trump would take prepared remarks and add comments about the economy, officials say. But lately he has tweeted less about the economy.

The Dow’s performance since Trump took office is now significantly less than what was achieved at the same point in Barack Obama’s presidency. The Dow is up 18 percent under Trump, compared with 45 percent at this point under Obama, according to Bespoke Investments.

Trump has repeatedly faulted the Federal Reserve for the market slide. But on Wall Street, many say Trump’s recent actions are also to blame.

“The market has lost confidence in the narrative coming out of the White House on the economy and trade,” said Joseph Brusuelas, chief economist at RSM, a multinational network of accounting firms.

Trump has publicly berated Powell, accusing him of raising short-term interest rates too quickly.

On Wednesday, Powell announced another rate increase — the fourth this year — and he said the Fed is lowering its economic outlook for 2019. U.S. markets pitched into a sell-off, extending losses that have piled up over the fall.

But the big sell-off this month was triggered when investors realized that the president had oversold his trade truce with China. Trump’s claims that China had agreed to reduce its tariffs on cars to zero and cut the U.S.-China trade deficit were never substantiated.

And just as the market seemed to stabilize, Trump and top Democratic leaders engaged in an Oval Office dust-up over border security that was broadcast live, raising fears of a government shutdown and of stalemate in Washington over the next two years.

“I am proud to shut down the government for border security,” Trump said as the Dow gave up a gain of more than 350 points and fell into the red.

The verbal brawl made for an unprecedented live television broadcast, and it showcased Trump’s struggles to reach agreements at home and abroad. Republican Senators, members of his own party, passed a bill to avert a shutdown that has no additional funding for a wall along the U.S.-Mexico border.

“The president may get the ‘art of the deal,’ but the art of the sale is to under-promise and over-deliver,” said Michael K. Farr, president of investment firm Farr, Miller and Washington. “U.S. investors understand they have to raise the verify part of the ‘trust but verify’ equation. Frustration is building.”

White House officials say Trump’s rhetoric on China, particularly the tweet describing himself as “Tariff Man,” rattled the confidence of U.S. investors and business leaders and caused the Dow to shed more than 1,100 points in a week.

The Dow and S&P 500 are expected to notch their worst December performances since 1931, a sign of how rapidly Wall Street sentiment is shifting on the businessman president and his ability to steer the economy.

“I think ‘Tariff Man’ was really a blunder. Even if it was just a negotiating tactic, the timing couldn’t have been worse on that,” said Stephen Moore, who worked on economic policy for Trump’s campaign and remains close to the president.

The deeper worry for Trump is whether stock market jitters will spill over into the broader economy. The economy is still showing many signs of strength, with a low unemployment rate, rapid hiring, robust consumer spending, and high business and consumer confidence. But if the market doesn’t rebound, that probably would cause investors and families to lower their expectations for the future and scale back spending.

Fewer than 40 percent of Americans expect the stock market to grow in the next year, according to a survey of 1,300 households by the Federal Reserve Bank of New York. That is the gloomiest outlook for stocks in the Trump era.

And almost half of chief financial officers think the economy will be in a recession in a year, according to the Duke University/CFO Global Business Outlook survey released this month.

There is widespread agreement among economists outside the White House that the economy will grow more slowly in 2019 as Trump’s tax cuts and extra government spending wear off. The debate is over how steep the decline will be.

“The U.S. economy can withstand interest rate increases and tariffs, just not at the same time,” said Jamie Cox, managing partner at Harris Financial Group. He blamed the deteriorating outlook chiefly on man-made problems: tariffs, Brexit and monetary policy.

The president often says China has more to lose than he does, and the Chinese are feeling the pressure. He is not going to back off the tariffs, several people said, and actually takes joy in how much Republicans dislike them.

“He knows it’s going to sting, it’s going to hurt,” said Doug Deason, a prominent donor with close ties to the White House. “But China is feeling the heat at this point. He knows if you don’t ask for much, you aren’t going to get much.”

Treasury Secretary Steven Mnuchin and top economic adviser Larry Kudlow have expressed concerns about the tariffs privately. But although Kudlow doesn’t like them, he has adopted the viewpoint that they are part of a broader strategy to target China.

Trump’s top economic and trade advisers blanketed the airwaves in recent days in an attempt to increase confidence in the U.S.-China trade talks and to play down any concerns about the market decline, but a lot remains to be bridged between the two sides in the next 90 days.

“There’s nothing in our data other than the financial market jitteriness that suggests the fundamentals are changing,” Kevin Hassett, Trump’s top economist, said recently.

The president has blamed a number of his officials for the sentiment shift on Wall Street, but he rants continually about Powell. At Trump’s Mar-a-Lago estate in Florida over Thanksgiving, the president complained about Powell extensively, guests said.

Powell took over the top Fed job in early February and has raised interest rates one percentage point since then, to a range of 2.25 percent to 2.5 percent, the highest rates in a decade, although still modest by historical standards.

Peter Navarro, who is one of Trump’s top trade advisers and pushes a hard stance against China, has tried to pin the entire market downturn on Powell.

“That’s a false narrative in terms of the impact of the tariffs on the stock market. My view is that this is strictly an interest rate effect,” he said recently on Fox News Channel. “I think the Fed went too far, too fast. And what we saw basically was a little asset reallocation from the stock to the bond market.”

But many economists and analysts said Trump could help limit market and economic declines if he finalized a deal with China by spring.

“Wall Street would applaud a terrible deal just to get it passed and have the uncertainty gone,” said Timothy Anderson, a trader and managing director of MND Partners.

Damian Paletta contributed to this report.