By David Morgan and Amanda Becker

WASHINGTON (Reuters) – President Donald Trump’s drive for the deep tax cuts that he promised as a candidate reached a major milestone on Thursday, with his fellow Republicans in the House of Representatives unveiling long-awaited legislation to overhaul the tax code.

The legislation called for slashing the corporate tax rate to 20 percent from 35 percent and reducing the number of tax brackets for individuals, according to a summary document obtained by Reuters.

Largely in line with expectations for the tax-cut plan they have been developing behind closed doors for weeks, the House tax-writing Ways and Means Committee proposed doubling the standard deduction for individuals and families, capping the deduction for state and local property taxes at $10,000 and maintaining the current tax treatment of 401(k) and IRA retirement plans.

The bill is the starting gun for a frantic race toward what Trump and Republicans in the House and Senate hope will be their first major legislative victory since he took office in January: the enactment this year of a package with up to $6 trillion in tax cuts over the next decade for corporations, small businesses and individuals.

The bill would create new a family tax credit, maintain deductions for mortgage interest for existing loans and newly purchased homes up to $500,000, double exemptions for estate taxes on inherited assets, repeal estate taxes after six years and allow small businesses to write off loan interest, according to the document.

Congress has not succeeded on comprehensive tax changes since 1986, when Republican Ronald Reagan was in the White House and Democrats controlled the House. Bipartisan cooperation led to the passage of that plan three decades ago, but Republicans have frozen Democrats out of the process of developing this legislation and passed a budget plan that would enable them to pass it with no Democratic votes.

Independent analysts have said that, based on an outline of the plan previously made public, corporations and the wealthiest Americans would benefit the most, and the federal deficit would be greatly expanded over the next decade because of a loss of tax revenue.

Trump said at the White House this week that he wanted Congress to pass the tax overhaul by the U.S. Thanksgiving holiday on Nov. 23.

The tax-writing House Ways and Means Committee has been drafting the bill, and Republican Chairman Kevin Brady has promised to release it on Thursday. A spokesman for Republican House Speaker Paul Ryan said it would be formally announced at 11:15 a.m. (1515 GMT).

Trump, House Republican leaders and Republican members of Brady’s panel will then meet at the White House on Thursday afternoon. Trump is also meeting separately with Republican senators, who must also unite to pass the tax plan.

“This is the beginning of the end of this horrible tax code,” Brady told reporters on Thursday as he entered a meeting with Republican lawmakers ahead of the bill’s release.

“We’re going to get it done,” added House Republican leader Kevin McCarthy.

Still, important issues remain unresolved and Brady himself predicts the initial legislation will change next week, when his panel is due to begin preparing it for an eventual House vote.

While Republicans control the White House and both chambers of Congress, intra-party differences have prevented them from passing major legislation sought by Trump, as exemplified by the collapse of their effort to dismantle the Obamacare law. Any failure to pass tax cuts legislation would call into question Republicans’ basic ability to deliver on promises.

The bill must also pass the Senate, where Republicans hold a slimmer 52-48 majority and earlier this year failed to garner enough votes to pass a major healthcare overhaul. Senate Republican leaders have said they aim to finish their work on taxes by year-end.

Democrats have criticized the proposed tax cuts as a giveaway to corporations and the wealthy that would harm workers and middle-class Americans.

(Reporting by Amanda Becker and David Morgan; Additional reporting by Susan Heavey and Susan Cornwell; Writing by Will Dunham; Editing by Lisa Von Ahn and Nick Zieminski)