Joe Manchin opens the door to backing Democrat-only infrastructure bill that rolls back 'unfair' Trump tax cuts

• Manchin signaled he could support a party-line infrastructure bill after striking a possible deal with Republicans.
• Manchin's backing is pivotal to the bill passing without GOP support.
• He also supports unwinding the Trump tax cuts, which he called "unfair."

Sen. Joe Manchin of West Virginia on Tuesday said he was open to backing a party-line infrastructure bill. It's one of the clearest signs yet that Democrats could pivot to approving much of President Joe Biden's spending plans without GOP support.

The influential Democratic centrist told NBC News that "human infrastructure" should constitute a follow-up package. Biden unveiled a sprawling package in May that would set up a paid leave program, universal pre-K, and community college among other social initiatives.

"I've come to the knowledge, basically, that budget reconciliation is for reconciling budgets. So it's money matters," he said. Reconciliation refers to a process that Democrats can use to approve spending bills with only a simple majority and guard them from a filibuster. Every Democratic senator would have to support a plan because of their narrow 50 seat majority in the chamber.

Manchin also said he believed "adjustments" need to be made to the 2017 Republican tax law, which slashed corporate taxes. He's previously said he backed lifting the corporate tax rate to 25% from 21% in a partial rollback of the law.

"Republicans have drawn a line in the sand on not changing anything, and I thought the 2017 tax bill was a very unfair bill, and weighted to a side that basically did not benefit the average American," he told NBC News.

Bipartisan negotiations that include Manchin on a $1 trillion package directed at physical infrastructure appeared to be headed into fresh trouble on Tuesday.

A group of centrist Republican and Democratic negotiators are struggling to finalize how to pay for the plan, given the White House ruled out a proposed increase to the gas tax and a new charge on electric vehicle drivers.

"I think it's gotten more complicated for the pay-fors," Republican Sen. John Thune of South Dakota told reporters. "There is even a bigger a bigger hole now."

Democrats are eyeing beefing up the IRS so it can better pursue wealthy tax evaders. But Republicans don't believe much revenue can be generated through tougher tax enforcement.

Some Democrats are hopeful about striking a deal with Republicans. But many are pressing for a larger package afterwards that includes clean energy, childcare, and other social provisions.

"I am equally determined to move ahead with a reconciliation package that will deliver on Biden's boldest policy proposals and I think it is possible for us to do both," Sen. Chris Coons, a Biden ally, told Insider last week. "But it's going to take a lot of coordination in our Democratic caucus, which I'm hopeful we'll be able to get done this month."