When Sen. Robert Menendez stands in a New Jersey courtroom Wednesday to face bribery charges, a lot more than his political future will be riding on the outcome.
For federal prosecutors, the case will be a test of whether they can still make corruption charges stick in the wake of a Supreme Court decision last year that tightly restricted the reach of the federal bribery law.
The case, the first against a sitting U.S. senator in nearly a decade, also might affect the delicate balance of power in the Senate, where a thin Republican majority has made it difficult for the party to pass legislation.
If the jury convicts Menendez, Republicans would try to boot him from office immediately, allowing Gov. Chris Christie, a Republican, to appoint his replacement. Democrats would seek to let him hang on to the seat at least until January — when Christie will leave office. Polls currently show a Democrat likely to succeed him.
Menendez, 63, once the powerful chairman of the Senate Foreign Relations Committee, is accused of taking gifts for years from a wealthy South Florida eye doctor, Salomon Melgen, including plane rides, a stay in a five-star Paris hotel and visits to a resort in the Dominican Republic with three different girlfriends.
Menendez failed to report any of the gifts on disclosure forms until news reports in 2013 made the trips public. Ultimately, he wrote the doctor a $58,500 check and said that the trips had slipped his mind.
Daniel Weiner, senior counsel at the Brennan Center for Justice, which advocates for tighter controls on money in politics, said the allegations in the case seem a throwback to an earlier, more colorful era of Washington corruption.
"No one goes to smoke-filled steakhouses anymore, they sleep on the floor of their offices and fly home on the weekends," he said. "This is good old-fashioned trips to the Dominican Republic on a private plane. There's something almost refreshing about it."
Over five months in 2012, Melgen also wrote $771,500 in checks to a legal expense fund and various political committees.
The government says that in return, Menendez used the power of his office to try to help Melgen. Prosecutors allege that the lawmaker worked to win visas for Melgen's foreign girlfriends and intervened in a contract dispute Melgen had in the Dominican Republic.
Melgen, an ophthalmologist in West Palm Beach, was once the country's top-billing doctor to Medicare. Much of the money went to pay for an expensive drug called Lucentis. According to prosecutors, Melgen would divide up one dose of the drug among several patients, then bill Medicare separately for each one.
In 2012, as Melgen was fighting a claim that he overbilled Medicare by $8.9 million, Menendez lobbied officials at the Department of Health and Human Services to advocate for Melgen's position that Medicare rules allowed him to divide up the dosages.
Eventually, Menendez enlisted the help of then-Senate Majority Leader Harry Reid of Nevada to get a meeting with Kathleen Sebelius, then the secretary of Health and Human Services. She declined to intervene in the case.
In a separate trial in South Florida, Melgen was convicted in April of 67 counts of Medicare fraud.
The key legal issue for Menendez's case is whether those accusations — many of which the defense does not deny — add up to bribery.
Defense attorneys will argue that the trips and flights don't make a crime. They point to a longtime friendship between Menendez and Melgen, which they say began long before Menendez was elected senator. The two spent holidays together with their families, lawyers said.
They say Menendez's attempts to help Melgen were just routine business for a senator. The favors he did for Melgen weren't "official acts" as defined by the federal bribery law, they assert.
That argument is quite similar to one the Supreme Court unanimously accepted last year when the justices threw out the conviction of former Virginia Gov. Bob McDonnell, ruling his actions didn't meet the legal definition of bribery. The justices found that although McDonnell set up meetings for a businessman who had provided expensive gifts and loans to his family, he didn't make any official decisions on his benefactor's behalf.
If Menendez's actions add up to a crime, "then the prosecution can indict any member of Congress, and more alarmingly, whichever members they choose to target," defense lawyers said in one filing.
The case has a strange history, beginning with allegations in 2012 that Menendez and Melgen were having sex with underage prostitutes. No basis was found for those reports, and Menendez later charged that he had been the subject of a smear campaign, either by Republicans or Cuban intelligence agents unhappy with his fierce opposition to the Castro regime.
But a federal investigation of those charges turned up evidence of the trips and other benefits.
Since his indictment in April 2015, Menendez and his attorneys have tried to have the charges thrown out, saying the case was tainted and arguing that Menendez's activities were protected by the Constitution. Federal judges weren't sympathetic, and in March, the Supreme Court declined to consider that argument in advance of the trial.
Menendez will be the first sitting senator to stand trial since Ted Stevens, the Alaska Republican who was convicted in 2008 of concealing $250,000 in gifts. That conviction was later thrown out when federal prosecutors were found to have hidden information from the defense, but by that time, Stevens had lost his bid for reelection.
Former prosecutors say the Menendez case will be another big test for the Justice Department's public integrity unit, which handles major political corruption cases.
"I'm sure this was heavily vetted by the front office for exactly those reasons," said one former prosecutor who discussed the case on condition of anonymity. "They don't need another embarrassment."
The trial, expected to last about six weeks, is not anticipated to feature a lot of argument over the facts — the government has assembled emails, credit card and phone records and interviews with dozens of witnesses to lay out the trips and the details of Menendez's work on behalf of Melgen.
In one email, Menendez asked Melgen to use his reward points to book him a luxury suite at the Park Hyatt Hotel in Paris for a three-night stay, specifying rooms that included a king bed and limestone tub with a rain shower.
In a brief this week laying out their view of the case, prosecutors said Menendez and Melgen were "hiding a corrupt pact spanning seven years" that began shortly after Menendez became a senator. Menendez's "relentless advocacy" for Melgen went far beyond what legislators typically do for constituents, they said.
If a jury buys the government's explanation, Weiner said the McDonnell ruling would not necessarily help Menendez.
"He used his position as a senator to pressure other public officials to do things, and the court was very clear, that counts," he said. "You have a powerful senator calling an embassy and saying, 'You've got to process this visa.' Sure, he's not the guy who is technically processing the visa, but that strikes me as more than an innocent suggestion."
Even if he beats the bribery charges, Menendez could have a tougher time explaining away his failure to mention the trips over five years of financial disclosures. After his relationship with Melgen came to light, Menendez released a statement that said he had taken three flights on Melgen's plane; in fact, prosecutors said, Melgen treated him to 20 flights.
Menendez has vowed to beat the charges and run for reelection in the fall of 2018. He is still raising money for a campaign and has $3.7 million on hand.
If Menendez is convicted, though, Democrats will face the awkward political question of whether to stand by the senator — and for how long.
Republicans would likely try to force him from office immediately, but that will be unlikely if Menendez vows to stay in office as he appeals. He could be removed by his fellow senators, but only on a two-thirds vote, meaning 14 Democrats would have to go along.
Harrison Williams, a New Jersey senator caught in the Abscam scandal, stayed in office for 10 months following his 1981 conviction. Stevens also refused to resign after his conviction, although his election loss came just days after the verdict.
How long Menendez would fight to stay in office, and who would choose a successor, is now "the big guessing game in the state," said Ross K. Baker, a Rutgers University political science professor who has studied the Senate closely, most recently embedded in Reid's Senate office. In spite of the corruption allegations, Baker said he didn't see any sign that Menendez's Senate colleagues would be quick to condemn him.
"They might be feeling, 'there but for the grace of God go I,'" he said. "He wasn't being treated like a pariah. He wasn't being shunned, he wasn't at all."