A road construction project backs up traffic in Springfield, Ill., in 2013. (Seth Perlman/AP)

When President Trump took office, some otherwise deeply disappointed Democrats thought they might be able to work with him on one marquee campaign promise: pumping $1 trillion into the nation’s roads, bridges, airports and other long-neglected infrastructure.

But any prospects for cooperation on that front seemed to largely evaporate this week, when Trump released a budget proposal that included deep cuts to existing infrastructure programs — angering Democrats and prompting many to question the president’s commitment to an issue he trumpeted as a candidate.

Trump’s budget proposes $200 billion in new federal spending on infrastructure over the next decade, an amount his administration argues will be sufficient to spur a promised $1 trillion in new investments once new spending by the private sector and state and local governments are factored in.

But Democrats, who want the federal government to spend much more on infrastructure, say the cuts to existing programs — including federal funding for local transit projects — far outstrip the proposed new spending.

Pedestrians walk past a Massachusetts Bay Transportation Authority train in Boston in 2015. President Trump has proposed cutting federal transit funding. (Steven Senne/AP)

“At best, this is just moving money around,” said Rep. John K. Delaney (D-Md.), who has spent four years pushing legislation that calls for additional infrastructure spending. “I think for every Democrat who looked at the Trump administration like I did, and hoped we could find common ground, this is a real punch in the gut.”

Senate Minority Leader Charles E. Schumer (D-N.Y.), whose office released an analysis citing $206 billion in proposed cuts to existing programs, took to the Senate floor on Wednesday, declaring that “President Trump’s campaign promises on infrastructure are crumbling faster than our roads and bridges.”

“It makes us very dubious of any attempt to do infrastructure by this administration,” Schumer said. “We hope we’re wrong. But the budget is a document that tells where the real truth is in terms of administration beliefs, and they sure as heck by this budget don’t like infrastructure.”

Cooperation from Democrats would be essential to any infrastructure plan that Trump might seek to pass in coming months. The new administration has sought to advance two of its other big priorities — health care and tax cuts — under legislative rules that make it possible to win approval with just Republican votes.

But that isn’t the case with an infrastructure bill, which would need at least some Democratic support in the Senate and will probably require Democratic votes in the House, where some conservative Republicans are wary of any new federal spending.

Besides setting aside money in the budget, separate legislation would be required spelling out how the Trump initiative would work.

Trump administration officials argue that the focus on the amount of federal dollars being spent misses the point of its infrastructure plans, which remain a work in progress.

A six-page “fact sheet” released along with the budget this week — the most detailed description of the initiative to date — argues the federal government should be seeking to better “leverage” its dollars to spur more private investment and, that in many cases, state and local governments are better equipped to move forward on their own.

“Our budget intends to dedicate $200 billion in federal funding to improve infrastructure but also to re-engineer the way our programs work to maximize co-investment from state, local and private parties and ensure that we can stretch all those dollars further by eliminating red tape,” said John Czwartacki, communications director for the Office of Management and Budget.

The budget formally unveiled Tuesday does not spell out how the $200 billion proposed by Trump would be dispersed. It suggests a gradual ramp-up in the new spending, with only $5 billion proposed for the coming fiscal year.

The administration is also contemplating privatizing some public assets, such as airports, bridges and highway rest stops, to generate funds to build new projects. Plans call for incentives to make private investments more attractive, including the likelihood of more toll roads. And the administration is pledging to cut regulations to speed up the time it takes to construct major projects.

At an event last week hosted by the U.S. Chamber of Commerce, Transportation Secretary Elaine Chao said “a key feature of the infrastructure plan will be unleashing the billions of dollars in private capital available for investment in infrastructure.”

Many transportation advocates were taken aback this week by the extent to which Trump proposed gutting existing programs.

The president, for example, proposed elimination of a program launched in 2009 by the Obama administration that is slated to provide nearly $500 million in grants to states and localities next year to help with an array of transportation projects.

Trump also proposed halting federal funding for new light rail and other local transit projects, a move that could save more than $900 billion next year. The administration said that such projects are better funded entirely at the local level and that “waiting for federal grant funding is not the most efficient way to meet . . . local transportation needs.”

Beth Osborne, senior policy adviser for the advocacy group Transportation for America, said the latter move is curious at a time when Trump should be seeking to expand the coalition of groups that will help him lobby Congress for more transportation dollars.

The transit dollars Trump proposed cutting are particularly important to urban areas, said Osborne, who served as senior transportation official in the Obama administration.

“They’ve started out by making a lot of people angry, and that’s not a good way to start,” she said. “It’s certainly not a great way to get Democrats excited about his initiative.”

One Democratic mayor whose city has benefited from federal transit dollars, Michael B. Hancock of Denver, called Trump’s proposals “really shortsighted and very contrary to what the president campaigned on.”

Hancock said it remains early in Trump’s term and there still is a chance for a meaningful infrastructure package to emerge, but he says “this is a huge missed opportunity.”

“This is one thing that Americans overwhelmingly support,” Hancock said of infrastructure spending.

Trump’s budget also takes aim at several infrastructure programs in rural areas, which formed a large segment of his political support last year.

The budget, for example, seeks to eliminate a program slated to spend nearly $500 million in the coming year for wastewater treatment projects in rural areas, something the administration says can be accomplished through other programs.

It is unclear how quickly a Republican-led Congress distracted by probes into Russian election meddling and other controversies might take up Trump’s infrastructure initiative once details are unveiled.

For now, lawmakers remain mired in a debate over a health-care bill and have signaled tax reform will be their next priority — meaning action on infrastructure could be months away.

Asked if the infrastructure debate could slip into next year, House Speaker Paul D. Ryan (R-Wis.) said at a forum hosted by the publication Axios on Wednesday that it remains “a priority” but that funding remains uncertain.

“I don’t know what the timing of that will be for that as much because we’ve got to come up with the fiscal space,” Ryan said.

Michael Steel, who was a senior aide to then-Speaker John A. Boehner (R-Ohio), said he believes it is still possible that a bipartisan agreement could be reached on an infrastructure bill in coming months. But, he said, “there’s no question that the white-hot anger Washington Democrats feel for President Trump is going to make it harder.”

On Thursday, a group of liberal Democratic lawmakers and progressive groups staged a rally outside the Capitol where they blasted Trump’s cuts and ticked off 10 principles that they will insist are part of any plan going forward. Among them: “Prioritize public investment over corporate giveaways and selling off public goods.”

The discord between the parties has left some dispirited about the prospects for a bill reaching Trump’s desk anytime soon.

William J. Sandbrook, president of U.S. Concrete, a Texas-based company that stands to benefit from an uptick in infrastructure spending, said he’s an “eternal optimist” but confessed that his outlook has dimmed recently.

“I’m not sure Trump’s dealmaking ability is going to be able to bridge that divide,” Sandbrook said. “This is just caught up in the politics.”