WASHINGTON (AP) — Sen. Bob Menendez has shown no sign he will voluntarily resign from the Senate following his conviction on bribery charges, leaving Democratic senators contemplating an expulsion effort to force him from office.

While Menendez, a New Jersey Democrat, has six months remaining in his term, Democrats have made clear they don’t want him in office any longer. Within minutes of the guilty verdict on Tuesday, Senate Majority Leader Chuck Schumer called for his resignation and New Jersey Gov. Phil Murphy, who would name Menendez’s replacement, said that the Senate should expel Menendez if he refused to step down.

Expulsion, which requires a two-thirds majority, is an exceedingly rare step in the Senate. The last time it was even seriously considered by the chamber was almost 30 years ago, and only 15 senators — almost all during the Civil War — have ever been expelled.

Still, senators are preparing to make the push.

“He must stand up now and leave the Senate. He must do that, and if he refuses to do that, many of us, but I will lead that effort to make sure he is removed from the Senate,” Sen. Cory Booker, New Jersey’s other Democratic senator, told MSNBC late Tuesday. “That is the right thing to do. That is the just thing to do.”

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After a jury found Menendez, 70, guilty of accepting bribes of gold and cash from three New Jersey businessmen and acting as a foreign agent for the Egyptian government, the senator did not comment on his political plans in brief remarks as he left the courthouse. But he vowed to appeal the verdict.

“I have never violated my public oath. I have never been anything but a patriot of my country and for my country,” Menendez told reporters.

It was a familiar refrain from Menendez, who has taken a defiant stand ever since he was first indicted in September last year.

While under indictment, Menendez stepped down as chair of the powerful Senate Foreign Relations Committee, but continued to attend classified briefings — a move that irked his fellow senators. And while they mostly ostracized him in the day-to-day workings of the Senate and over half of the Senate Democratic caucus called for his resignation, there was little they could do to force him from office, especially when Schumer maintained that Menendez should get his day in court.

Now that Schumer has urged Menendez to resign, there will be a concerted effort to put as much pressure as possible on Menendez to voluntarily step aside. That started Tuesday as the Senate Ethics Committee released a statement saying that it would “promptly” complete an investigation into Menendez that started when he was first indicted. The committee also made it clear that recommending expulsion to the Senate was on the table.

In the meantime, any individual senator could move to hold a snap vote on expulsion for Menendez, though that effort could be blocked by an objection from any other senator — including Menendez himself.

That means that many in the Senate will likely wait for the ethics committee to release its recommendation.

In the past, an expulsion recommendation from the panel has been enough for disgraced senators to voluntarily resign. In 1982, the panel recommended that former Sen. Harrison A. Williams, Jr., a New Jersey Democrat, be expelled and he resigned before it went to a vote in the full Senate. In 1995, Sen. Robert W. Packwood, an Oregon Republican, announced he would resign just a day after the committee released its recommendation.

“Most people, even most members of Congress, have enough of a sense of shame that they would rather not have the last big news item about them be that they got expelled,” said Josh Chafetz, a professor at Georgetown University Law Center who has studied congressional powers.

As the November election approaches, the appetite among Democrats to rid themselves of a besmirched colleague will only increase. Four Democrats in tough reelection races, Sens. Bob Casey of Pennsylvania, Jacky Rosen of Nevada, Jon Tester of Montana and Tammy Baldwin of Wisconsin, have already indicated they support expulsion.

If Menendez resigns or is expelled, it would be left to Murphy, the Democratic governor, to fill the seat. Several prominent New Jersey Democrats have called for Rep. Andy Kim, who won his party’s nomination for the Senate seat, to be appointed. Kim, a third-term congressman, said Tuesday he would accept if offered the seat.

Kim’s strength in the race drove Tammy Murphy, the wife of the governor, out of the primary. Tammy Murphy had backing from much of the state’s political establishment, but Kim outpolled her and she withdrew from the race in March.

It is still possible the governor could appoint his wife to the seat, even temporarily, although he ruled out that scenario during a radio interview in October. A spokesperson for the governor said Wednesday he would not comment on potential replacements for Menendez, who has previously said he is running for the seat as an independent.

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Associated Press writer Wayne Perry in Atlantic City, N.J. contributed to this report.