Voters head to the polls in Alabama on Tuesday for the state's Republican U.S. Senate primary. The race to fill Attorney General Jeff Sessions' former seat has featured an endorsement from President Donald Trump and attacks on Senate Majority Leader Mitch McConnell. In Alabama, a deep-red state that overwhelmingly backed Trump, the Republican who emerges from the field will most likely win the special election. Several Republicans are vying for the seat, but only three are considered serious contenders: Luther Strange, Roy Moore and Mo Brooks. Strange, the incumbent, was appointed to fill the Senate seat in February after Sessions became the top U.S. law enforcement official. An average of recent polls shows the front-runner is Moore, who was removed as Alabama chief justice in 2003, with about 32 percent of support. Strange followed with roughly 27 percent. Brooks, a congressman and member of the far-right House Freedom Caucus, has about about 18 percent, according to RealClearPolitics. If no candidate wins 50 percent of the vote, the top two go to a runoff next month.

Luther Strange

Trump endorsed Strange, 64, on Monday, saying in a tweet that the senator "is strong on Border & Wall, the military, tax cuts & law enforcement." Luther Strange of the Great State of Alabama has my endorsement. He is strong on Border & Wall, the military, tax cuts & law enforcement. Since he took office, Strange has voted in line with Trump's views about 92 percent of the time, according to RealClearPolitics. Strange, who stands at an imposing 6-foot-9-inches tall, previously spent six years as Alabama's attorney general. Before that, he was a lawyer in Birmingham. Senate Majority Leader Mitch McConnell also prefers Strange in the race. Trump endorsed the Alabama incumbent even as tensions between him and McConnell increase.

Roy Moore

Moore, 70, was removed as chief justice in 2003 for opposing the removal of a Ten Commandments statue from the state Capitol. After being elected to be chief justice in 2015, he was suspended from the position a year later. He told judges to uphold Alabama's law against same-sex marriage despite the Supreme Court legalizing it nationwide. He later resigned to seek the Senate seat. Moore has cast himself as an anti-establishment candidate and touted policy positions similar to Trump's. In a recent AL.com column, he highlighted as his priorities "rebuild[ing] our military," "securing the border," cutting taxes and regulations and checking "activist judges."

Mo Brooks

Morris Brooks Jr., 63, first got elected to the House in 2010. As a staunch fiscal conservative, Brooks has backed efforts to chop federal spending. He joined the House Freedom Caucus earlier this year in initially opposing the GOP plan to replace Obamacare, saying it did not go far enough to dismantle the law. Brooks eventually supported it after the bill got amended. During the campaign, he has repeatedly slammed McConnell and Strange, contending they represent embedded Washington interests. He has called McConnell the "swamp king," a reference to Trump's pledge to "drain the swamp."

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