Story highlights Roy Moore is running as the anti-establishment Republican

This race could determine how future races will play out for Republicans

Sen. Luther Strange has the backing of Trump and McConnell

Washington (CNN) Sen. Luther Strange and Roy Moore have one final day of campaigning before Republican voters in Alabama will take to the polls in a GOP primary to decide who they want to run against Democrat Doug Jones in the special election to fill a US Senate seat.

Strange, who was appointed by then-Gov. Robert Bentley to finish out the term after Jeff Sessions became attorney general, is running against Moore, the former chief justice of the Alabama Supreme Court in the GOP primary.

Strange is seen as an establishment Republican who has strong support from President Donald Trump and Senate Majority Leader Mitch McConnell to keep the seat, which Sessions had held for two decades. He has been propped up by more than $9 million in spending from the Senate Leadership Fund, a super PAC aligned with McConnell.

Trump boosted Strange on Twitter Tuesday morning: "Luther Strange has been shooting up in the Alabama polls since my endorsement. Finish the job - vote today for 'Big Luther.'"

Meanwhile Moore, a hardline conservative Christian, has cast the campaign as an opportunity to reject McConnell -- a much less popular figure among Alabama Republicans than Trump. He has the support of Steve Bannon, the recently ousted former White House chief strategist, and former Alaska Gov. Sarah Palin.