(Reuters) - A federal judge on Wednesday threw out several bribery charges against Democratic U.S. Senator Bob Menendez, five days after U.S. prosecutors announced they would seek to retry him after his first trial ended with a hung jury.

FILE PHOTO: Sen. Bob Menendez (D-NJ) looks on during a Senate Banking Committee hearing on Capitol Hill in Washington, U.S. January 23, 2018. REUTERS/Aaron P. Bernstein/File Photo

The New Jersey politician, who is expected to run for reelection this year, is charged with accepting gifts, including luxury trips and campaign contributions, from wealthy ophthalmologist Salomon Melgen in exchange for official favors.

U.S. District Judge William Walls, who presided over last year’s corruption trial, said on Wednesday that prosecutors had failed to show that some $660,000 in political contributions from Melgen to benefit Menendez’s 2012 reelection campaign were part of any bribery scheme.

The mere fact that some of the money arrived around the same time that Menendez took actions that could benefit Melgen was not enough to prove a “quid pro quo” arrangement, Walls said.

“There is no there there,” he wrote, quoting the writer Gertrude Stein.

But the judge refused Menendez’s request to dismiss the rest of the case, saying enough evidence existed to permit a jury to decide his guilt.

Prosecutors have accused Menendez of accepting bribes from Melgen and, in exchange, lobbying Medicare officials to alter their billing practices after the agency concluded Melgen had overbilled it.

Melgen, who is Menendez’s co-defendant in New Jersey, was separately convicted of a massive Medicare fraud in Florida.

Menendez is also charged with helping Melgen’s foreign girlfriends obtain visas and attempting to intervene in a port dispute involving one of Melgen’s companies.

Defense lawyers argued at trial that Melgen and Menendez were simply close friends.

Menendez’s lawyer, Abbe Lowell, said on Wednesday the remaining case “is now solely about the purest of personal hospitality allegations,” including trips on Melgen’s private plane and vacations at his home in the Dominican Republic. He said he hopes the Justice Department reconsiders its decision to retry the senator.

A Justice Department spokeswoman said prosecutors were reviewing the court order and considering their next steps.

The first trial, which lasted more than two months, ended in a mistrial when the jury in Newark, New Jersey, could not come to a unanimous verdict on any count.

A new trial date has not been set.

The prospect of a second trial during a campaign year has not deterred the state’s prominent Democrats, including U.S. Senator Cory Booker and newly elected Governor Phil Murphy, from continuing to back Menendez. He currently faces no serious opponent for the Democratic nomination.