Posted by Senator Robert Menendez of New Jersey announced on Thursday that he would not run for re-election as a Democrat this year, bowing to intense political pressure and federal charges that place him at the center of an international bribery scheme.
But in a nine-minute video posted on social media, Mr. Menendez, 70, insisted he would be exonerated at a trial scheduled to begin in May and he left the door open to running as a political independent if he is cleared.
“I am hopeful that my exoneration will take place this summer and allow me to pursue my candidacy as an independent Democrat in the general election,” he said.
Still, Mr. Menendez’s decision to forgo the competition for his party’s nomination amounted to a painful concession that his political career was teetering on the edge.
He was all but certain to lose the June primary for his own seat. Nearly every Democratic ally has abandoned him in recent months, and two prominent Democrats — Representative Andy Kim and Tammy Murphy, the wife of Gov. Philip D. Murphy — are trouncing him in primary polls.
“Unfortunately, the present accusations I am facing — of which I am innocent and will prove so — will not allow me to have that kind of political dialogue and debate with political opponents who have already made it a cornerstone of their campaign,” he said in the video on Thursday.
A campaign as an independent is unlikely to be much easier, even if he were to prevail in court. It could also jeopardize Democrats’ already tenuous hold on the Senate.
Although polls show that as many as three quarters of New Jersey voters believe Mr. Menendez is guilty of the charges against him, he could still siphon enough votes from the Democratic nominee to tip a close race.
Even just preserving the possibility in the short run, though, allows Mr. Menendez to continue raising money to pay the lawyers representing him and his wife, Nadine Menendez.
He had already spent $2.3 million from his campaign account on legal fees from October through December, federal filings show. He has spent at least $295,000 more from a separate legal defense fund. Those costs are likely to spike in the weeks ahead as his trial approaches.
Mr. Menendez’s legal troubles have been a nonstop distraction since September when he and Ms. Menendez were charged in an elaborate bribery scheme. Hours before Mr. Menendez’s announcement, his wife appeared in federal court in Manhattan for a hearing on whether her lawyers would be precluded from representing her at trial because of a potential conflict of interest.
Mr. Menendez’s daughter, Alicia Menendez, a news anchor on MSNBC, was on the air, filling in as the host of “Deadline: White House,” when details about her father’s announcement began to spread.
Mr. Menendez’s announcement was the latest twist in the slow-motion collapse of a man who just six months ago was seen as among the most powerful political figures in New Jersey and a leading national voice on foreign policy and immigration issues.
Mr. Menendez effectively outran the law for decades as he rose from mayor of his hometown, Union City, to one of the country’s first Cuban American members of Congress. He avoided charges in one federal criminal inquiry. Then, after being indicted in 2015 on separate bribery charges, he avoided conviction two years later when the trial ended in a hung jury and the government dropped the case after the judge dismissed the most serious charges.
The case was costly nonetheless. Mr. Menendez spent more than $5 million on lawyers, and a little-known challenger got nearly 40 percent of the vote in the Democratic primary the next year. Party leaders rallied behind Mr. Menendez in the general election, and he defeated his well-funded Republican opponent, Bob Hugin, by 11 percentage points.
Mr. Menendez insisted that history could repeat itself when federal prosecutors in Manhattan initiated the latest round of charges in September. But longtime allies who had stood by him through his earlier travails concluded that this case was different and cut their ties to him.
In July, before the charges were announced, John F.X. Graham, a New Jersey insurance executive and member of the Democratic National Committee, donated $10,000 to Mr. Menendez’s defense fund.
But Mr. Graham said in an interview this week that he felt “betrayed and disappointed” after the details of the government’s case against Mr. Menendez emerged.
He said he had told Mr. Menendez’s fund-raising consultant that he would never again contribute. In response, he said he got a handwritten note from the senator assuring him he would “beat this thing.”
“Bob Menendez’s career is over,” said Mr. Graham, who believes Mr. Menendez should resign. “It’s that simple and he just hasn’t admitted it to himself yet.”
An initial indictment last fall said Mr. Menendez and his wife had conspired with others to accept gold bars, a Mercedes-Benz convertible and other lavish bribes in exchange for using his position as chairman of the Senate Foreign Relations Committee to aid a foreign power, Egypt, and throttle two criminal investigations in New Jersey.
The charging papers included photos of the gold, wads of cash and the Mercedes, all of which were found during a search of the senator’s home.
In the months since then, prosecutors have added more than a dozen charges, accusing Mr. Menendez and his wife of plotting to have him act as a foreign agent, taking steps to aid another foreign nation, Qatar, and obstructing justice.
The couple and two other defendants have pleaded not guilty to all counts. But a fifth defendant, a former New Jersey insurance broker, pleaded guilty this month to trying to bribe the couple with the Mercedes. In a setback for the senator’s defense, the former broker, Jose Uribe, has agreed to cooperate with prosecutors.
Mr. Menendez, a skilled and pugnacious political fighter, has accused those prosecutors of being overzealous and trying to smear him, making his case directly to fellow senators and voters. His lawyers argue that the indictment criminalizes normal legislative activity and flouts constitutional protections afforded to members of Congress.
Those arguments may prevail in court, but they have had little effect on the voters, Democratic officials and even some members of his own staff who would have helped determine his political fate.
Nearly 75 percent of New Jersey voters disapprove of Mr. Menendez’s Senate performance, a recent Monmouth University poll found — roughly the same percentage that consider him guilty.
In Washington, Mr. Menendez has been urged to resign by more than half of the Senate’s Democrats. His longtime political adviser and some key congressional staff members quit.
Back at home, if he remains on the ballot in November, he will most likely face either Mr. Kim or Ms. Murphy, who are locked in a highly competitive race for the Democratic nomination.
There are several Republican primary contenders, including a mayor and a former television reporter, both of whom have endorsed former President Donald J. Trump as the party’s standard-bearer this year, and a hotel developer from the Jersey Shore who has been critical of Mr. Trump.