Alabama voters, peppered by slick ads, outside influences and dueling endorsements during a fierce six-week campaign, get the last word today when they pick a Republican nominee for the U.S. Senate.

They will choose between former state Supreme Court Chief Justice Roy Moore and Sen. Luther Strange in a race that brought President Trump and other political heavyweights to Alabama.

The president again tweeted his support for Strange early Tuesday morning.

Today's winner advances to face

on Dec. 12.

The prize is the Senate seat Jeff Sessions left to became Trump's attorney general.

Strange has held the seat on an interim basis since accepting the appointment by former Gov. Robert Bentley in February.

Polls open at 7 a.m. statewide and close at 7 p.m.

Trump endorsed Strange before the Aug. 15 primary and spoke at a nationally televised rally for Strange on Friday night in Huntsville. A super political action committee controlled by Senate Majority Leader Mitch McConnell has spent heavily on ads attacking Moore.

Strange has made the Trump endorsement the centerpiece of his campaign, touting what he says is a close relationship with Trump that bodes well for the president's agenda and for Alabama.

"I believe we're going to support our president by voting for me on Tuesday," Strange said during the only debate of the runoff campaign last Thursday night.

Moore has pledged to support Trump's agenda, as well, and says he's confident Alabama voters won't yield to the influence of the Senate establishment that backs Strange.

During the debate Thursday night, Moore challenged Strange to explain the circumstances of his appointment by Bentley, which came while Strange was attorney general and Bentley was under investigation for possible ethics violations.

Strange ignored Moore's question and said Moore lacked a firm grasp of issues.

Strange has previously said he made no deals with Bentley and noted that Bentley ultimately resigned from office under a plea deal.

Strange says he built a strong record fighting corruption, including the prosecution of former House Speaker Mike Hubbard at the time Hubbard was one of the state's most powerful politicians.

Strange also emphasizes his record of joining with other Republican attorneys general in challenging initiatives of President Obama on the environment, immigration and religious liberty.

"I'm proud of that record," Strange said. "That's a common sense conservative record."

Moore entered the Senate race after the Alabama Court of the Judiciary suspended him for the remainder of his term last year. The court found Moore violated judicial ethics by directing probate judges to enforce the Alabama ban on same-sex marriage despite the U.S. Supreme Court ruling that states had to allow and recognize gay marriage in the case Obergefell v. Hodges.

Moore makes no apologies and criticized Strange for not fighting the Supreme Court.

"As soon as Obergefell came down, he caved," Moore said during the debate. "He did not stand."

The Court of the Judiciary also ended Moore's first term as chief justice in 2003 after Moore refused to follow a federal judge's order to remove a Ten Commandments monument that Moore had placed in the state judicial building.

Moore said he has proven that he will fight "liberal judges," just as he fought as a West Point graduate in the Vietnam War.

Trump said one reason he came to campaign for Strange is because he thinks Strange is more of a safe bet to defeat Democrat Jones in December.

Trump said if Moore wins the primary he will be "campaigning like hell" for Moore to defeat Jones.

The race is important for the balance of power in the Senate, with Republicans now holding a slim majority with 52 seats.

Moore led a nine-candidate field in the Aug. 15 primary with 164,000 votes, 39 percent, to 139,000 for Strange, 33 percent.

Seventy-two percent of those who voted in the primary voted on the Republican side.

A new state law prohibiting crossover voting is in effect for the first time today. Those who voted in the Democratic primary will not be allowed to vote in the Republican runoff.

The new law won't have any effect on the Dec. 12 election or any general election. It only applies to party primary runoffs.