TALLAHASSEE, Fla. — Calling Washington “horribly dysfunctional,” Florida Gov. Rick Scott is challenging U.S. Sen. Bill Nelson in an election that could be one of the most expensive races in the nation.

The Republican governor was expected to criticize “career politicians” and call for term limits for members of Congress while formally announcing his campaign on Monday.

“I admit that Washington is horribly dysfunctional,” Scott said.

“Washington is full of old thinking. Washington is tired. And the truth is, both political parties share some of the blame. They’ve tried a lot of things — it just didn’t work. But I will not accept the idea that we can’t change Washington.”

Scott is a multimillionaire businessman who never ran for office before his successful governor’s race in 2010. He campaigned as part of the Tea Party movement and called for massive budget and tax cuts, but was forced to scale back his plans amid opposition from the GOP-controlled Legislature. He also changed his hard line positions on immigration.

Scott is leaving office due to term limits, and had been urged to challenge Nelson, Florida’s only statewide-elected Democrat, by President Donald Trump.