A group of Democratic senators wants to overhaul international taxation, introducing a new proposal Monday that would help pay for President Biden’s $2 trillion infrastructure plan. The senators are focused on changing three specifics of the 2017 tax law passed under President Donald Trump, claiming the provisions created new incentives to ship jobs overseas and reforms would also be an investment in American workers. 

Their proposal comes as the tax debate is about to heat up in Washington as Biden’s plan already faces hurdles in Congress, including with some Democratic lawmakers.

“Congress needs to ensure mega-corporations pay their fair share to fund critical investments in the American people,” said Senate Finance Chair Ron Wyden of Oregon. “That starts with ending incentives to ship jobs overseas and closing loopholes that allow companies to stash their profits in tax havens, and, instead, rewarding companies that invest in the United States.”

The senators’ plan focuses on increasing the tax rate on U.S. multinational corporation foreign earnings and setting it on a country-by-country basis. It’s similar to Mr. Biden’s own proposal, but the lawmakers left the door open on the tax rate — be it matching the U.S. corporate tax rate or setting it slightly lower, as the president has proposed, at 21%. Their plan also aims to create incentives to invest in innovation in the United States rather than offshoring factories, restoring full credits for domestic investments and curtailing the largest corporations from eroding the U.S. tax base.

“For decades, our tax code has rewarded corporations that shut down production in the U.S. and move American jobs overseas, and the 2017 Republican tax law only made it worse, with its 50 percent off coupon for corporations that move jobs to Mexico or China,” said Senator Sherrod Brown, of Ohio.

“We need an international tax system that rewards companies making investments here in the U.S., particularly in cutting-edge technologies that will dictate the future success of our economy and ability to create good-paying jobs,” said Senator Mark Warner.

The Virginia Democrat said Monday he has already expressed some concerns with the Biden infrastructure plan. While he would not comment on the specifics of the president’s proposal to raise the U.S. corporate tax rate from 21% to 28%, he said he wanted to go through the plan in much more detail than he has so far. 

His comments come after Senator Joe Manchin also said Monday that he does not support increasing the corporate tax rate to 28%. In a radio interview with Hoppy Kercheval, the West Virginia Democrat said the corporate tax rate should be 25%. Manchin also said he’s not the only Democrat who felt strongly about it, stating there were six or seven others who did as well. 

“We have to be competitive,” Manchin said. “And we’re not going to throw caution to the wind.”

The 50-50 split in the Senate, with Vice President Kamala Harris serving as the potential tie-breaking vote, gives centrists like Manchin substantial power when weighing in on legislative proposals moving forward. Manchin said Monday if he does not vote to get on it, “it’s not going anywhere.”

But Mr. Biden reiterated his support Monday for raising the corporate tax rate from 21% to 28% and dismissed concerns it would drive businesses overseas.

“We were talking about a 28% tax that everybody thought was just fair enough for everybody,” he said. “51 or 52 corporations of the Fortune 500 haven’t paid a single penny in taxes for three years. Come on, man.”

Speaking to reporters during Monday’s briefing, White House press secretary Jen Psaki said there would be different ideas to pay for the infrastructure plan, and there would be different tax proposals and a range of questions that congress will have to address in terms of pay-fors and how those would work.

“This will be all part of the discussion,” Psaki said, which she characterized as in early stages.

The Biden administration briefed members of Congress last week on the infrastructure plan. On Tuesday, Treasury Secretary Janet Yellen is set to brief House Democrats. 

Alan He contributed to this report.