Democratic lawmakers want to raise caps on federal spending. So do many Republicans. But despite the desires of each party’s congressional leadership, President Donald Trump is refusing to go along, possibly complicating his re-election bid.

In its latest federal spending request, the White House proposed a steep hike in the Pentagon budget for fiscal 2020 — an unsurprising move by a Republican president who has vowed to “rebuild” the U.S. military. But Trump and his team would keep existing spending caps in place.

Unless the president signs a caps deal, existing law would shrink the current $716 billion defense budget cap to $576 billion and take the nondefense limit from $597 billion to $543 billion.

He would instead swell defense budgets through a gimmick: Giving the Pentagon an additional $165 billion via a war fund both parties long have called a “slush fund” and another $9 billion in emergency funds. At the same time, Trump wants to cut Medicare, Medicaid and Social Security, all popular programs he vowed as a candidate to safeguard.

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The 2011 Budget Control Act mandates across-the-board cuts to both military and domestic programs that both parties have resisted since they were put in place. On a bipartisan basis, lawmakers have supported raising the caps in the past — with the support of Presidents Barack Obama and Trump.

But White House aides say Trump is fed up with how much the government spends, saying he is unlikely to support another caps-raising deal. What some have called a gamble heading into a re-election campaign, others interpret as another gesture to his conservative base, which has long expressed concern about Washington’s spending habits — until actual spending cuts get close to reality.

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Republican lawmakers, including leaders, are becoming more and more vocal about raising the spending limits. But the White House remains dead set against it.

“We are opposed to a caps deal. Democrats still haven’t written a budget and are already talking about busting the bipartisan spending restrictions they agreed to previously,” a senior administration official said.

Only it’s not just Democrats.

Senate Budget Chairman Michael B. Enzi of Wyoming has floated the idea of a “cap adjustment.” And House Minority Whip Steve Scalise said he “hoped” lawmakers would be able to reach agreement on the 12 annual spending bills before the new fiscal year begins Oct. 1.

House and Senate appropriators are expected to write their spending bills at levels above the caps, so a deal would be necessary as would a change in statute.  House Majority Leader Steny H. Hoyer said Thursday that Senate Majority Leader Mitch McConnell “wants a caps deal reached.”

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That leaves Trump and acting White House Chief of Staff Mick Mulvaney — a former conservative GOP congressman from South Carolina — as the key holdouts.

“I’ve talked to Mr. Shelby,” Hoyer said, referring to Senate Appropriations Chairman Richard C. Shelby of Alabama. “I’ve talked to the White House about a caps deal. Unfortunately, I don’t think Mr. Mulvaney wants to reach a caps deal — he wants to use it as leverage as opposed to allowing us to proceed in the regular order.”

G. William Hoagland, who was an aide to former Senate Majority Leader Bill Frist, said the spending standoff is “a very bad political position for the president to be in. If the president holds to this position going into 2020, we are most likely to begin 2020 with another shutdown situation.”

Hoagland, now with the Bipartisan Policy Center, said that “doesn’t sound like a winning position for Republicans and the president in 2020,” considering a shutdown or stopgap funding bill would affect federal agencies like the Federal Aviation Administration, which is dealing with Boeing’s Max airliner problems, those charged with border security amid what Trump calls a “crisis,” and other big-ticket items. 

Still, the White House is holding firm.

“The president’s budget meets the caps Congress set, provides the resources necessary for our national security, and cuts wasteful Washington spending,” the senior administration official said.

Jennifer Shutt contributed to this report.