(Restores dropped word "he" in first paragraph)
WASHINGTON (Reuters) -U.S. Representative Mo Brooks of Alabama, a close ally of former President Donald Trump who helped lead a Republican effort to challenge the 2020 presidential election results in Congress, is expected to announce on Monday whether he will run for the U.S. Senate in 2022.
Brooks - a staunch conservative who was scheduled to appear at a rally in Huntsville, Alabama, with former Trump adviser Stephen Miller - is seen as a potential favorite to replace Republican Senator Richard Shelby. Shelby, 86, has announced his retirement.
Brooks has said he has spoken to Trump about a possible Senate run and would announce his plans on Monday.
"Heading to Huntsville, Alabama for a big announcement tonight with @MoBrooks_. The America First movement is only just beginning," Miller tweeted on Monday, referring to a Trump policy slogan.
Trump won Alabama handily in November, besting Democrat Joe Biden in the state by more than 25 percentage points. A Trump endorsement could put Brooks ahead in a field of Senate contenders that already includes Lynda Blanchard, who served as Trump's ambassador to Slovenia.
Another Republican, Alabama Secretary of State John Merrill, is seen as a potential Senate candidate, as well as Democratic U.S. Representative Terri Sewell.
Brooks, 66, backed Trump's false claims of widespread voter fraud in the 2020 election and spoke at a Trump rally that preceded the deadly Jan. 6 Capitol riot, when violent Trump supporters stormed Congress in an attempt to overturn Biden's victory. The violence, which left five people dead, led to Trump's second impeachment in the House of Representatives and acquittal in the Senate.
After encouraging "patriots" at the Trump rally to start "taking down names and kicking ass," Brooks was named in a federal lawsuit brought by Democratic Representative Eric Swalwell. Swalwell, who helped prosecute the impeachment case against Trump, is seeking financial damages for the injury and destruction caused by the riot.