The Alabama election to replace Jeff Sessions in the U.S. Senate is headed to a crowded and likely expensive GOP primary, the field swelling Wednesday to 11 candidates on the last day of qualifying

The messy primary is the type some Senate powerbrokers had hoped to avoid as appointed Sen. Luther Strange, backed by a super PAC with ties to Senate Majority Leader Mitch McConnell, faces challengers from different wings of the GOP.

The race will gauge the preferences of conservative voters in the deeply red state.

U.S. Rep. Mo Brooks— a member of the House Freedom Caucus — and former Alabama Supreme Court Chief Justice Roy Moore, who twice lost his position for stances on the Ten Commandments and gay marriage, are among those challenging Strange.

Others in the GOP field include: Christian Coalition president Randy Brinson; Birmingham businessman Dom Gentile; state Sen. Trip Pittman; Bryan Peeples; Mary Maxwell; Joseph F. Breault; James Paul Beretta; and Karen Haiden Jackson.

“It will certainly be expensive. There will be a lot of outside money pouring into the state,” said former Alabama Republican Party Chairman Marty Connors.

Strange was appointed to the Senate in February by then-Gov. Robert Bentley, who resigned last month amid fallout from an alleged affair with a top staffer.

Bentley had planned for a 2018 Senate election, but new Gov. Kay Ivey, moved it up to this year, setting up what’s expected to be a summer demolition derby among Alabama’s dominant Republicans.

Connors said the key for challengers will be to try to make it into a primary.

Eight Democrats are seeking the seat, including former U.S. Attorney Doug Jones.

The other Democratic candidates are: Will Boyd; Vann Caldwell; Jason Fisher; Michael Hansen; Robert Kennedy Jr.; Brian McGee; and Nana Tchienkou.

It has been two decades since a Democrat represented Alabama in the U.S. Senate.

The primary will be Aug. 15.