A state senator considering a conservative bid for Senate in Louisiana has opted out of the race, and is instead backing Rep. Bill Cassidy (R-La.) in his challenge to Sen. Mary LandrieuMary Loretta LandrieuProject Veritas at risk of losing fundraising license in New York, AG warns You want to recall John McCain? Good luck, it will be impossible CNN producer on new O'Keefe video: Voters are 'stupid,' Trump is 'crazy' MORE (D).

State Sen. Elbert Guillory (R), who has switched parties twice since 2007, endorsed Cassidy in the race, calling on supporters "to join me in rolling up your sleeves, getting to work, for Louisiana’s next Senator — Dr. Bill Cassidy."

Guillory told the Times-Picayune that he decided to support Cassidy after multiple conversations with him, and said he believes "there's a need for us to unify and pull together."

He suggested Cassidy would be a "departure" from the problems in Washington.

"I believe we should be doing something different and I believe Dr. Cassidy will represent a major departure toward values and away from the idiocy that we read on the front pages coming out of Washington," Guillory said.

Guillory was considered a potential challenger to Cassidy, and launched a super- PAC earlier this year to boost black conservatives running for office.

Cassidy is facing the threat of a challenge from the right in his bid. He's taken fire from both national and local conservatives for his support of a measure similar to ObamaCare during his time in the state legislature and his previous support of Democratic candidates.

A number of national conservative groups have already endorsed his primary conservative challenger, Air Force veteran Rob Maness.

Guillory had floated the idea of running earlier this year, and could've further complicated GOP chances of taking down Landrieu if he ran.

Landrieu remains one of her party's most vulnerable incumbents, and one of the GOP's top four targets in its pursuit of Senate control.

Because all candidates, regardless of party, are included on the initial ballot in Louisiana, multiple GOP candidates in the race run the risk of splitting the Republican vote and sending the race to a runoff, where Republican fortunes are less certain.

But Cassidy appears to be gathering Republicans behind him. Another state lawmaker who was considering a GOP bid for Senate, Rep. Alan Seabaugh, announced last month he wouldn't be running, and also threw his support behind Cassidy.