WASHINGTON — Hoping for victories as he nears the 100-day mark, President Trump has struggled this week to advance his agenda in the Republican-controlled Congress, thus far failing to bend lawmakers to his will, even those in his own party.

He attempted to use a looming government shutdown to leverage funding for his proposed border wall, but Democrats called his bluff. And his demands at a second try to repeal the Affordable Care Act also have proven ineffective.

On Wednesday, he plans to unveil a tax cut proposal that would offer a reduced, 15 percent business tax rate to corporations and, in some cases, smaller businesses. (Story, B11.) But the plan faces an uphill battle.

So far, it appears to be business as usual in the nation’s capital — with little getting done.

Trump campaigned as a Washington outsider who would use his corner office savvy to strike deals and get stuff done. But his tactics — pushing his position on Twitter, seeking out high-pressure moments to gain an upper hand, often catching lawmakers of both parties by surprise — aren’t bearing fruit.

What remains to be seen is if Trump is learning anything from his recent legislative stumbles. Some lawmakers are optimistic, despite his limited successes.

Republican Senator Lindsey Graham of South Carolina, who hasn’t been shy about criticizing Trump, said that the president’s understanding of Congress from Inauguration Day until now has improved “one hundred percent,’’ and that Trump has done more outreach in 100 days than former president Barack Obama did his entire time in office.

“It’s compromise, it’s a give-and-take proposition here,’’ said West Virginia Senator Joe Manchin, a Democrat. He pointed to the 2013 immigration bill that passed the Senate with bipartisan support, and included increases to border security funding, but went nowhere in the House. Manchin has discussed reviving that effort with Trump. “I think the more he starts understanding, and people explain, he learns more about that. There’s other pathways forward,’’ he said.

One must-do on Trump’s agenda this week is help Congress to avert a partial government shutdown by enacting a short-term spending bill by midnight Friday.

In addition to that, his big order of business this week will be the corporate tax cut proposal. The package is expected to seek a rate of 15 percent from the current 35 percent, which would add exponentially to annual budget deficits.

Trump may be headed to a morass in this area, too. Again, Republican leaders on the Hill have scant details. The broad outlines that have leaked to the press suggest he will be on a collision course with budget-conscious Republicans, especially House Speaker Paul Ryan, whose own tax overhaul plan would balance tax cuts with a new levy on imports that would raise close to $1 trillion in revenue, along with eliminating other loopholes.

Trump’s experience with funding the multibillion-dollar Mexican border wall (stymied so far) and his efforts to cajole lawmakers into passing a replacement for the Affordable Care Act (foiled in March, delayed in April) do not portend huge breakthroughs on taxes.

“He’s finding out that the skills he may have used to cut real estate deals don’t translate very well on Capitol Hill,’’ said Jim Manley, a veteran of the officies of former Senate minority leader Harry Reid and former Massachusetts senator Ted Kennedy.

Late last week, the White House started pressuring congressional leaders to include a down payment for the wall in the must-pass spending bill needed to keep the government open beyond Friday. The push started with Trump’s White House budget chief, Mick Mulvaney, and other Trump officials. Trump weighed in over the weekend with a series of tweets.

Then, almost as suddenly as he created the conflict, the president blinked. Trump told conservative media reporters at a White House event Monday evening that he is comfortable delaying border wall funding until September, when Congress will have to hammer out its next spending bill.

The relief among Republicans on Tuesday was palpable.

“I think he’s made a wise decision,’’ said Maine Republican Senator Susan Collins.

“It was a question of what’s doable,’’ said Alabama Senator Richard Shelby, a lawmaker who is supportive of Trump’s border wall proposal.

“Nobody wants a government shutdown, over anything,’’ Shelby said.

Senate majority leader Mitch McConnell, while avoiding any mention of Trump’s wall, said he is optimistic negotiators can reach a deal on keeping the government funded “in the next few days.’’

The wall’s final price tag ranges from $21 billion to more than $70 billion, depending on whom you ask. Trump made it clear Tuesday that he’s not backing off.

“The wall’s going to get built, folks. In case anybody has any questions, the wall is going to get built,’’ he said in brief comments as he signed his latest executive order. “And the wall is going to stop drugs and it’s going to stop a lot of people from coming in that shouldn’t be here and it’s going to have a huge effect on human trafficking, which is a tremendous problem in this world.’’

Lawmakers who represent districts on the US-Mexico border, such as Republican Representative Will Hurd of Texas, have called Trump’s proposal ill-advised. “I’ve said time and time again that building a wall from sea to shining sea is the most expensive and least effective way to secure the border,’’ Hurd said in a statement.

“I want to see money for border security, that means drones, towers, that means sensors, increased capabilities,’’ said Senator John McCain, Republican of Arizona.

“I’m not talking about a concrete wall,’’ McCain quipped. “I’ve been to China.’’

Republican senators seemed to bend over backward to give Trump an opening to claim eventual victory on the wall by raising the prospect of a border security approach that doesn’t completely involve a wall. Maybe it’s a partial wall, maybe it’s a fence in parts, or drones and other technology.

Trump’s wall is more metaphorical than literal, insisted Thom Tillis, a Republican senator from North Carolina.

“I think we can be less prescriptive about exactly what the structure looks like, and more focused on the fact that we need to secure the border.’’

Arizona Senator Jeff Flake was more blunt.

Echoing criticisms of other border-state lawmakers, he said: “It’s always been a more complicated picture than a campaign slogan.’’

Trump was also forced to backtrack on another showdown he was trying to orchestrate — a second effort to repeal the Affordable Care Act.

Republicans’ first attempt to fulfill their promise to scrap the law collapsed messily when Ryan and Trump couldn’t secure enough votes from their own party.

But congressional GOP leaders and aides told reporters they needed to devote this week to keeping the government open, and that a deal to get enough health care repeal votes in the House — while progressing — was not yet in hand. They never scheduled the vote.

Material from the New York Times was included in this report. Victoria McGrane can be reached at victoria. mcgrane@globe.com..