Trump tax cuts gain momentum as Rand Paul goes 'all in'

WASHINGTON, Oct 20 (Reuters) - U.S. Republican senator Rand Paul on Friday appeared to back the Trump administration's sweeping tax cut plan, saying he was "all in" for massive tax cuts even as the Senate passed a key budget measure without his support one day earlier.

On Thursday, the Republican-controlled Senate approved the budget resolution for the 2018 fiscal year, with Paul casting the lone Republican vote against it. That approval paves the way for their tax-cut proposal that would add up to $1.5 trillion to the federal deficit over the next decade to pay for the cuts.

SEE ALSO: Trump says Senator Paul will vote for tax cuts

U.S. President Donald Trump on Friday signaled optimism for passage of the cuts, saying Paul would back the proposed tax measure when it comes up for a vote.

"The Budget passed late last night, 51 to 49. We got ZERO Democrat votes with only Rand Paul (he will vote for Tax Cuts) voting against," Trump wrote on Twitter. "This now allows for the passage of large scale Tax Cuts (and Reform), which will be the biggest in the history of our country!"

Paul responded with his own tweet, saying, "I’m all in for tax cuts @realDonaldTrump. The biggest, boldest cuts possible - and soon!"

The Kentucky Republican had said he would not vote for the budget measure unless it in kept in line with previously enacted federal budget spending caps.

Republicans are still hammering out their tax legislation after releasing an initial outline. The administration has said it would deliver up to $6 trillion in tax cuts to businesses and individuals.

Republicans, who also control the U.S. House of Representatives and the White House, are under pressure to succeed on tax reform after failing to make good on another key agenda item, their years-long pledge to scrap Obamacare, the signature healthcare law of Democratic former President Barack Obama.

Trump is also seeking his first major legislative victory since taking office in January amid a tumultuous tenure overshadowed by ongoing investigations into Russia's alleged interference in the 2016 election, as well as a series of the president's comments that have sparked controversy.

Democrats remained united in their opposition to the budget bill and are unlikely to support the Republicans' tax plan, arguing it would benefit the wealthy, raise taxes on some middle-class Americans and widen the federal deficit.

Still, Trump made clear his preference for a bipartisan tax bill while meeting with members of the Senate Finance Committee from both parties on Wednesday, Republican Senator John Cornyn told reporters.

The Senate's budget must be reconciled with a markedly different version passed by the House, a process lawmakers have said could take up to two weeks. (Reporting by Susan Heavey; Editing by Mark Heinrich and Bill Rigby)