By Andy Sullivan and Jason Lange

WASHINGTON (Reuters) -Republican candidates who echoed former President Donald Trump's false claims of a stolen presidency were defeated in high-profile nominating contests in Colorado on Tuesday ahead of November's midterm elections.

The two Colorado candidates, U.S. Senate hopeful Ron Hanks and Tina Peters, who had sought the Republican nomination to be Colorado's top election official, are among dozens of Republicans who support Trump's denial of his 2020 election loss, prompting concerns that U.S. democracy could be at risk.

But Edison Research projected that Hanks, who marched in the Jan. 6, 2021 attack on the U.S. Capitol that aimed to overturn Trump's loss to Democrat Joe Biden. would lose the Senate primary to businessman Joe O'Dea, who has rejected Trump's election fraud claims.

Likewise, Edison projected that Peters, who has been indicted for election tampering and barred from overseeing voting in her home county this year, would lose the Colorado secretary of state primary to Pam Anderson, a county clerk who has also dismissed Trump's baseless allegations.

Those defeats came on a day when a congressional committee investigating the Jan. 6 attack heard testimony from a former Trump White House aide that she had been told he tried to take control of his presidential limousine that day when his security detail declined to take him to the Capitol where his supporters were rioting.

In another election, Illinois state senator Darren Bailey, who was endorsed by Trump, was projected by Edison Research to win the Republican nomination for governor over Aurora Mayor Richard Irvin, a more moderate Republican who was seen as a greater threat to incumbent Democratic Governor J.B. Pritzker.

In New York, incumbent Governor Kathy Hochul was projected by Edison Research to win the Democratic nomination over two rivals. Hochul took the job last year when former Governor Andrew Cuomo resigned while facing sexual harassment allegations.

With Biden's approval ratings underwater, Republicans are favored to win control of the House of Representatives, where they need to flip only five Democratic seats for a majority, and could also take over the Senate.

A Republican-controlled House could stymie Biden's legislative agenda and launch politically damaging investigations into his administration.

Several incumbent lawmakers in Illinois faced off against each other, as the state lost a seat in Congress due to its shrinking population.

Republican Representative Mary Miller held a narrow lead over rival Representative Rodney Davis. Miller caused controversy at a rally with Trump on Saturday when she said that the Supreme Court's decision to revoke the nationwide right to abortion was a "victory for white life."

Miller's aides say she meant to say "right to life," but Davis says it is further evidence that she is unfit for office, citing previous controversial comments.

Miller has been endorsed by Trump and has backed his false claims of a stolen election. Davis, by contrast, broke with his party last year to back the congressional inquiry into the Jan. 6 attack.

The winner of the race is expected to win re-election in November in a largely rural, Republican-leaning seat.

In the Chicago suburbs, Democratic Representative Sean Casten led rival Marie Newman in a similar battle between incumbents for a newly drawn seat. Newman faces an ethics investigation for allegedly promising a job to a political rival.

In western Colorado, firebrand Republican Representative Lauren Boebert was projected by Edison to fend off a challenge from state Senator Don Coram, who has argued that she is too extreme.