Idaho Sen. Jim Risch is set to announce Wednesday that he will throw his weight behind Sen. Marco Rubio in the 2016 contest, the Florida Republican's third senate endorsement in as many days.

A Risch spokesman confirmed the impending announcement to the Washington Examiner.

The Idaho senator's endorsement comes a day after Montana Sen. Steve Daines announced his decision to back the Florida senator, and two days after Rubio snagged the support from Colorado Sen. Cory Gardner. The endorsements all come less than a week after Rubio's widely praised performance at the third GOP debate in Boulder, Colorado.

"As members of the Senate's Intelligence and Foreign Relations committees, Marco and Risch work together on some of the toughest challenges facing America's security in the 21st century," Rubio spokesman Alex Conant said in a statement to The Examiner. "We welcome his support for Marco's campaign for president."

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