U.S. Sen. Bob Menendez (D – New Jersey) goes on trial Monday – accused of corruption. And this isn’t the first time.

Menendez has represented New Jersey in the United States Senate for nearly 20 years, and for much of that time, he's been accused of corruption.

“He has been a completely unethical, unprincipled politician for the entire time I've known him,” former New Jersey Gov. Chris Christie said in an interview in January. “And I've known him now for over 20 years."

Christie investigated Menendez in 2006 when he was the U.S. Attorney for allegedly steering federal grants to a nonprofit group in exchange for hundreds of thousands of dollars in rent on a property he owned. No charges were filed. Menendez was back on the hot seat in 2017, this time accused of accepting luxurious trips from a wealthy Florida doctor in exchange for political favors. Menendez claimed the doctor was simply a friend and the case ended in a hung jury.

Menendez called out his critics in a March 2018 interview. “To those who were digging my political grave so they could jump into my seat - I know who you are and I won’t forget you,” he said.

Menendez was indicted again last year, this time accused of taking hundreds of thousands of dollars in bribes from three New Jersey businessmen. The senator and his wife, Nadine, will have separate trials. Hers is tentatively set for July.

In court filings unsealed last month, Menendez’s attorney indicated the senator might attempt to throw his wife under the bus, claiming she committed the criminal behavior and he was unaware of it.

Menendez has maintained his innocence but is not seeking the Democratic nomination in the primary next month. He's left open the possibility that, if exonerated, he might seek reelection as an independent.