Donald Trump returns to Washington on Thursday to rally support from Republican lawmakers and the business community following his historic criminal conviction in his New York hush money trial.

The former president, who is running to unseat Joe Biden in November, will have separate closed-door sessions with House members at a private club near the US Capitol and with senators at their campaign headquarters nearby, and address dozens of CEOs.

"The speaker and the House GOP Leadership look forward to hosting President Trump on Thursday morning to discuss growing the House Republican majority and the 2025 legislative agenda," a spokesman for House Speaker Mike Johnson told AFP.

It will be Trump's first meeting with lawmakers on Capitol Hill since leaving the White House in 2021 and his first trip to Washington since he was convicted in New York in May on all 34 felony counts of falsifying business records.

The party has circled the wagons around its standard-bearer since the guilty verdicts, with numerous lawmakers denigrating a justice system they baselessly claim is biased against conservatives.

House Republicans face an uphill battle to reclaim the lower chamber from the Democrats in November's elections, which are expected to be tight from the presidential race down through many of the key House and Senate contests.

Senate Republicans have a much more favorable map, and are confident of flipping their 49-51 minority in the upper chamber.

At least five centrist senators have yet to commit to attending on Thursday, although Minority Leader Mitch McConnell, who has not spoken to Trump since berating him from the Senate floor over the 2021 insurrection, has said he will be there.

- 'Anti-business' -

Trump was impeached for inciting the attack, when a mob of his supporters stormed the Capitol seeking to prevent the peaceful transfer of power to Biden, who beat Trump by more than seven million votes.

"I said three years ago, right after the Capitol was attacked, that I would support our nominee, regardless of who it was, including him... And of course, I will be at the meeting," McConnell told reporters.

Thursday's events are expected to be more of an effort to boost morale and ensure the party is moving in one direction ahead of the election than to drill down on specific policy proposals.

But Trump is likely to be quizzed on plans to extend the tax cuts he implemented in 2017, as well as his proposals for a tough illegal immigration crackdown and his view of the war in Ukraine.

The conflict has exposed fissures between Trump's isolationist "America First" movement and more traditional conservatives who want to see Russia's Vladimir Putin defeated with the help of American weapons.

The former president is also due to make his case for a White House return to chief executives at a meeting of Washington lobby group Business Roundtable.

Political news outlet Axios quoted a source familiar with Trump's expected remarks who said the former president was likely to focus on his plan "to immediately reduce inflation and roll back anti-business Biden regulations."

An election forecast model combining state and national polls with economic indicators, out Wednesday from The Economist, gives Trump a two-in-three chance of winning reelection. The same model four years ago had Biden at 83 percent.