A second Republican state legislator who previously considered a Senate bid of his own in Louisiana has instead endorsed the campaign of GOP Rep. Bill Cassidy.

Cassidy’s Senate campaign announced Monday that state Sen. Elbert Guillory had joined state Rep. Alan Seabaugh as the latest potential foe to get behind his challenge to Democratic Sen. Mary L. Landrieu — a top target of national Republicans.

Guillory gained some national attention this spring after switching parties. He had joined the Democratic Party in 2007, but he switched back to the GOP in May and became Louisiana’s only black Republican state senator.

The congressman will still have Republican company in the all-party primary next November. Despite a weak recent fundraising quarter, retired Air Force officer Rob Maness has won the backing of national tea-party-affiliated groups such as the Senate Conservatives Fund and the Madison Project.

Unless a candidate reaches 50 percent, the top two finishers in the primary will advance to a runoff in December.

The race is rated a Tossup by Rothenberg Political Report/Roll Call.