By Veronica Stracqualursi and Alex Rogers, CNN

(CNN) -- Former President Donald Trump on Wednesday endorsed Rep. Mo Brooks' campaign for US Senate in Alabama, supporting the controversial GOP congressman who stood by him during two impeachments and led the House effort to object to the 2020 election results.

"Few Republicans have as much COURAGE and FIGHT as Alabama Congressman Mo Brooks," Trump said in a statement.

Serving in his sixth term in the House, Brooks is seeking the Senate seat left open by retiring GOP Sen. Richard Shelby.

With Trump's endorsement, Brooks is expected to lock up the GOP nomination against Senate candidate Lynda Blanchard, Trump's former ambassador to Slovenia, who is less well-known in the state but boasts the ability to self-fund her campaign.

"With President Trump's endorsement, it's clearly Mo's race to lose," former Alabama Republican Rep. Bradley Byrne told CNN.

After Trump's announcement, Blanchard said that she would continue to run and has been "unwavering" in her support of him "since the day he came down the escalator in June 2015." Blanchard has put $5 million of her own money into her campaign.

"He is the greatest President of my lifetime, and I intend to go to Washington as the United States Senator from Alabama to represent the America First agenda that President Trump championed every day," she said.

Now out of office, Trump has signaled he plans to use his popularity to get behind Senate candidates in his mold -- to the fears of some GOP operatives tasked with winning back the Senate who worry that Trump will back candidates who could struggle in statewide races.

Brooks has been a strong ally of Trump's and was one of the first congressional members to publicly state he would object to the certification of Joe Biden's victory in the 2020 presidential election. He also boosted Trump's baseless claims of widespread fraud in the 2020 election.

In his endorsement, the former Republican President said Brooks "will protect our Second Amendment, combat the Biden open borders agenda" and "is fighting for voter integrity (like few others)."

At the January 6 "Stop the Steal" rally, Brooks told the crowd, "Today is the day American patriots start taking down names and kicking ass." Hours later, the pro-Trump mob stormed and ransacked the US Capitol to try to stop Congress from certifying Biden's victory.

CNN previously reported that his inflammatory remarks led some House Republicans to privately advocate for stripping Brooks from his committee assignments for some time.

Brooks announced his campaign for Senate last month, with an introduction by former Trump adviser Stephen Miller. Before jumping into the race, Brooks had spoken to Trump about running for Senate, CNN previously reported.

While Trump is popular in Alabama, he doesn't boast a perfect record in picking Senate candidates there. In 2017, Trump backed Sen. Luther Strange, who was appointed to fill Attorney General Jeff Sessions' seat, only to see Strange lose to Judge Roy Moore in the special election's GOP primary. Trump then endorsed Moore, and stuck with him even after several women accused Moore of sexual misconduct while they were underage, which Moore denied. Moore then lost to Democrat Doug Jones.

But Trump proved his ability to destroy a Republican candidate in the 2020 Alabama Senate primary. Trump endorsed former Auburn football coach Tommy Tuberville over Sessions, who lost his favor when he recused himself from overseeing the investigation into Russia's meddling of the 2016 presidential election. Tuberville trounced Sessions, who had been beloved in the state, and then Jones.