President Trump’s election-year push for a $1 trillion infrastructure spending bill to boost the struggling economy faces strong opposition from Senate Republicans.

GOP senators are warning that Trump’s expected proposal is too “rich” and would be a “heavy lift” in Congress, especially considering significant policy differences between Senate Majority Leader Mitch McConnell (R-Ky.) and Speaker Nancy Pelosi (D-Calif.).

House Democratic leaders have vowed to approve a surface transportation bill with a price tag around $500 billion over five years by the end of this month, which could put pressure on the GOP-led Senate. The House Transportation Committee is scheduled to start marking up that bill Wednesday.

McConnell has repeatedly warned about the impact of the surging federal deficit on future generations and has put the brakes on passing another expensive coronavirus relief bill. McConnell’s more pressing priority, say GOP senators, is to move a five-year reauthorization of the Highway Trust Fund estimated to cost $287 billion, well below the $1 trillion plan Trump is currently considering.

But even that modest plan is having trouble moving ahead because of internal disagreements over how to pay for it.

Senate Finance Committee Chairman Chuck Grassley (R-Iowa), who is in charge of coming up with a plan to pay for the surface transportation reauthorization bill, said members of his panel still need to come up with ways to cover $93 billion — a big chunk — of its price tag.

Asked about a news report that Trump is getting ready to unveil a new $1 trillion infrastructure spending proposal, Grassley said whatever bill Senate Republicans come up with “could be a lot less.”

At the very least, the Senate GOP plan “won’t be over that,” he added.

If the House and Senate are able to pass their respective surface transportation bills, the final measure — and the ways to pay for it — would be ironed out in conference.

Several Senate Republicans poured cold water on Trump’s call for another huge spending measure.

Sen. Pat Toomey (R-Pa.), a member of the Finance Committee, said, “I think that’s a very heavy lift.”

Senate Budget Committee Chairman Mike Enzi (R-Wyo.), who is also a senior member of the Finance panel, said the priority should be addressing the coronavirus pandemic directly and noted that a large portion of the $2.2 trillion CARES Act as well as the $484 billion interim coronavirus relief legislation passed in April has yet to be spent.

“For the last few days I’ve been talking about not paying for the national parks’ infrastructure. A trillion is a lot more than the $17 billion we’re talking about there,” he said, referring to the Great American Outdoors Act, which is still pending on the Senate floor.

“Nothing we’re doing right now is fiscally responsible,” he said, although he acknowledged that proponents of additional spending think it’s “economically responsible” to pump hundreds of billions of additional dollars into the economy.

“I’m much more inclined to stick to solving the virus problem,” Enzi said.

McConnell in late April quashed the idea of including an infrastructure component in the next round of coronavirus relief legislation.

“Infrastructure is unrelated to the coronavirus pandemic that we’re all experiencing and trying to figure out how to go forward,” he told Fox News at the time.

“We need to make sure that whatever additional legislation we do is directly related to this pandemic,” he added.

Trump’s plans to move a major infrastructure package before the election received fresh attention Tuesday after Bloomberg News reported that his administration is preparing a $1 trillion proposal.

News of the plan largely caught GOP senators by surprise.

When Trump tweeted in late March that he wanted a “VERY BIG & BOLD” infrastructure package costing $2 trillion, Republican senators mostly ignored the request.

Sen. John Cornyn (R-Texas), another member of the Finance panel, said the administration is going about it backward by coming up with a $1 trillion price tag before laying out what it would be spent on.

“You don’t start with the price tag. You start with what it is you want to accomplish and figure out what that is. Seems to me to be the opposite way to approach this by starting it with how much money you’re willing to spend,” he said.

Sen. Rob Portman (R-Ohio), also a Finance Committee member, said “the trillion dollars may be a little rich.”

But Portman said there are potential areas of common ground.

“I think there are areas where we can do something. Rural broadband is very popular among many of my colleagues,” he said.

He noted there are ongoing disagreements over how to pay for the Highway Trust Fund reauthorization, which Senate GOP leaders had planned to move this year before the COVID-19 pandemic wreaked havoc with the schedule.

“It’s already been passed out of committee, the question is how to pay for it,” he said.

The Environment and Public Works Committee approved the Senate highway bill in July, and it has languished since.

Bloomberg reported that Trump’s plan is being developed by the Department of Transportation and would set aside money for roads, bridges, 5G wireless and rural broadband. Elaine Chao, who is married to McConnell, is Trump’s Transportation secretary.

Given the difficulty of coming up with ways to pay for a $287 billion highway bill, a $1 trillion infrastructure initiative would likely add significantly to the federal deficit, which the Congressional Budget Office projects will reach $3.7 trillion in 2020.

A $1 trillion plan from the administration would double the $500 billion green infrastructure bill that House Democrats rolled out earlier this month.

Sen. Lisa Murkowski (R-Alaska) is one of a group of Senate Republicans who supports moving a big infrastructure plan.

She said part of the problem is a lack of coordination between the Senate and House.

“The question is, ‘What does it look like? Where do we put it? Is it something within the next [COVID-19] relief? Is it a stand-alone?’ ” she said.

Murkowski said she and other colleagues argue the best strategy is to combine the highway reauthorization bill that passed out of committee last year with the water infrastructure act that the Environment and Public Works Committee approved in May.

The water infrastructure legislation would provide $17 billion in new federal authorizations for infrastructure projects.

She said those two items could be combined with her American Energy Innovation Act, which stalled on the floor in March. The bill would have created incentives to develop energy efficiency improvements, supported wind and solar technologies, and promoted new energy storage technologies.

Senate Appropriations Committee Chairman Richard Shelby (Ala.) is another Republican proponent of a new infrastructure spending bill.

“I’ve advocated that for years,” he said. “I wish we had already done it.

“It could be, long-term, as meaningful as anything we could do, but I want to see the particulars,” he added when asked about Trump’s $1 trillion proposal.

Shelby said he hasn’t had any recent conversations with senior administration officials about the expected plan.