Now that Donald Trump has proved the Washington establishment wrong by winning the presidential election, his next hurdle will be getting the Congress he railed against to go along with the often scattershot policy proposals that buoyed his victory.

The Republicans who will control both chambers of Congress after Tuesday night’s sweep share party loyalty with the president-elect, an advantage that will almost certainly mean swift action on Trump’s promised conservative Supreme Court nominee. But the clarity ends there.

Trump reportedly met Wednesday with advisers to hash out his goals for his first 100 days in office, with a key focus on a transition plan that was delivered to Trump Tower the day before. Aides have focused on things Trump can do unilaterally, such as rolling back regulations, CNN reported.

Big spender?

But Trump has offered few specifics on many of his core policy proposals — including campaign-defining pledges to build a wall along the Mexican border, to improve infrastructure, and to revive the American manufacturing industry. But a common thread to many of his ideas is bound to rankle both the elites and the far-right in the party that he now leads: They would require a lot of government money.

And though Trump’s presidency will begin with a much friendlier legislative branch than what President Barack Obama has dealt with for the last six years, he will still face the challenge of uniting a party that fractured around his very nomination and a Senate majority that falls short of the 60 votes needed to overcome a filibuster.

“I hope he’s got thick skin, because he’s about to catch a whole lot of incoming [fire], and it’s not necessarily all going to come from Democrats,” said Mark Harkins, a senior fellow at The Government Affairs Institute at Georgetown University. “This budget stuff is very hard.”

Trump can make inroads on a few of his core proposals through executive actions, such as repealing Obama’s 2014 order protecting undocumented immigrants from deportation or making limited adjustments to international trade agreements.

Others, such as his stated priority to repeal the 2010 health care law — a goal that would require Democratic support in the Senate — he and Republicans in Congress could chip away at through the appropriations process.

Over the course of a four-year term, such incremental and marginal actions could amount to modest change. But if Trump has let on anything about his potential governing style during the last year of his campaign, it’s that he prefers dramatic gestures.

Glaciers move faster

Enacting sweeping changes will require buy-in from a Congress that prefers deliberation. This is a body that has had trouble passing even routine spending bills for many years, including during periods of unified government. Policy experts predict that, even with Republicans controlling all three branches of government, the task will not be easy.

“It’s hard to say how Trump will govern, but he seems like the type to hold a grudge,” said Brandon Rottinghaus, a political science professor at the University of Houston. “That’s a dangerous thing in a political environment that requires give and take.”

If he has provided any road map to his first priorities in office, it would be his victory speech Wednesday morning. He said he planned to “fix our inner cities and rebuild our highways, bridges, tunnels, airports, schools, hospitals.” He would “take care of our great veterans who have been so loyal.” And he would “double our growth and have the strongest economy anywhere in the world.”

Policy experts said Trump will most likely start with issues that have bipartisan appeal — such as improving infrastructure and child care — or that align with the GOP’s stated agenda — such as his tax proposal, which closely matches much of a tome House Speaker Paul D. Ryan released in June.

Trump’s unexpected success in Rust Belt states like Michigan and Wisconsin — considered a major factor in his victory — will also likely prod him to move early on his promise to renegotiate the trade policies that many blue-collar voters feel have cost them their jobs, but that could put him at odds with pro-business members of his party who support free trade.

Affordable child care advocates said Trump’s proposals for paid maternal leave and child care tax credits would likely get bipartisan support.

“That’s why we saw it from both candidates who were running for president,” said Michelle McCready, chief of policy at Child Care Aware. “It is a core issue that our country is grappling with.”

Patricia Cole, senior director of federal policy at Zero to Three, a nonpartisan group that focuses on early childhood development, said Trump’s support of the issue was a coup.

“This is not a Republican issue or a Democratic issue, it’s really a baby and family issue,” she said.

Friendly fire

But most of Trump’s proposals will encounter resistance, even within his own party.

“Most of his major proposals, like any presidential candidate, require resources,” Harkins said. “The wall needs money. The infrastructure stuff he was talking about last night needs money. Reforming the tax code to give back to the American people, that needs resources. … The question becomes, in an era of high budget deficits of over half a trillion dollars, where are we going to find those resources?”

Harkins said Trump’s options would include cutting domestic programs, reforming entitlement programs or allowing the national debt to increase — all tactics that would face fierce resistance from factions in the Republican Party.

“This country is hard to change, and when you have control of all the levers, you believe that’s what you were elected to do,” Harkins said. “I think they’ll find out there’s a math problem with a lot of what they want to do. They internally can’t solve it, and I can tell you the Democrats aren’t going to help them.”

In his corner, Trump will have advocates like Alabama Sen. Jeff Sessions, an early backer who appeared at Trump’s victory party. Sessions, though, has built a reputation as a deficit hawk and might have to pivot to advocate for Trump’s programs.

Michele Swers, a political science professor at Georgetown University, warned against underestimating Trump’s ability to get Congress to spend. She said that members might feel grateful to Trump that a forecasted down-ballot massacre failed to materialize.

Swers also pointed out that George W. Bush — the last Republican in the Oval Office — managed to get Congress to pass Medicare Part D, which added hundreds of billions of dollars to the national debt.

“He’s their standard-bearer,” she said. “He’s got a lot of clout with them at the moment.”

Rottinghaus, of the University of Houston, said Trump might not need to realize some of his more outrageous proposals to appease much of his base.

“If he did, he would face an immediate road block in Congress,” Rottinghaus said. “These are not reasonable solutions to complex problems.”

Voters don’t want a physical wall as much as they want the sense of job security Trump promised it would bring, he said. They don’t want a Muslim ban as much as the sense of safety from the threats Trump associated with those who practice the religion.

Trump also comes to office with a broad swath of support that defies party molds, a base he could leverage to appeal for public support if he faces resistance in Washington.

And then there’s the question of 2018.

Democrats will be defending 25 of the 33 states holding a Senate election next cycle, including up to a dozen vulnerable Democratic incumbents running for re-election in conservative or competitive states. Republicans then have an opportunity to reach a filibuster-proof majority in the Senate.