WASHINGTON — President Donald Trump’s road to getting legislation through Congress this year to restore the nation’s crumbling infrastructure appears increasingly precarious.

Trump has yet to release a plan despite his campaign pledge to create jobs by building bigger and better transportation and other types of infrastructure projects. Administration officials have said a plan will be released in the third quarter of this year, but Congress is unlikely to tackle the issue right away.

Lawmakers will have too much other must-pass legislation on their agenda when they return to work after Labor Day, including deadlines to raise the federal debt limit and, separately, prevent a government shutdown after the current budget year ends on Sept. 30.

After that, Republican leaders plan to revamp tax laws, always difficult and time-consuming.

Even if Congress moves on to infrastructure after taxes, Democrats and many Republicans are skeptical that Trump can reach his goal of generating $1 trillion in infrastructure spending over 10 years if he relies on tax incentives for companies that invest in projects in exchange for the right to collect tolls or other fees and speeding up the environmental permitting process.

Trump has said he’s hopeful Democrats will support his plan. Democrats say they want to work with the administration on infrastructure, but that any bill must include direct funding for projects, not merely tax credits for investors.

“We Democrats sent the president our ‘Better Deal’ infrastructure proposal in January. We still haven’t heard from them,” said Senate Minority Leader Chuck Schumer, D-N.Y.

Democrats would pay for their $1 trillion plan with unspecified cuts in tax breaks. In July, Schumer and House Minority Leader Nancy Pelosi, D-Calif, made the plan a key part of Democrats’ new economic agenda and messaging strategy for the 2018 midterm elections.

Trump’s budget proposal submitted to Congress in May called for using $200 billion in government spending to leverage $800 billion in local and private infrastructure investment over 10 years, but didn’t provide details. Trump separately proposed cutting current transportation programs, including eliminating subsidies for Amtrak’s long-distance trains and for scheduled airline service to rural communities, sharply reducing grants for transit capital projects and killing “TIGER” grants for difficult-to-fund transportation projects involving multiple jurisdictions or multiple transportation modes.