First elected to Congress in 1992, Mr. Menendez is now charged with taking bribes of gold, cash and a luxury car in exchange for trying to aid the governments of Egypt and Qatar, and seeking to disrupt separate criminal investigations involving his allies in New Jersey.

After his arrest, he stepped down, as required, as chairman of the Senate Foreign Relations Committee, but he has refused calls to resign and left open the possibility that he will run for re-election in November if he is exonerated at trial. This is his second federal bribery trial in seven years. In the earlier case, a jury was unable to reach a verdict and the charges were later dismissed.

Mr. Daibes is accused of giving Mr. Menendez furniture, gold and cash. These were bribes, prosecutors say, for Mr. Menendez’s efforts to have unrelated federal bank fraud charges Mr. Daibes faces in New Jersey quashed and for the senator’s help in lining up financing for a stalled real estate project.

Prosecutors say that Mr. Hana, a United States citizen born in Egypt, helped to arrange meetings with the senator and Egyptian officials that led to a lucrative monopoly for Mr. Hana’s company, IS EG Halal. The company, which certifies that products shipped to Egypt are prepared according to Islamic law, was used to funnel bribes to the Menendezes in exchange for the senator’s s efforts to steer U.S. weapons and aid to Egypt, according to the indictment.

Ms. Menendez served as a go-between for Mr. Menendez, Egyptian intelligence officials and men who were seeking political favors from the senator, according to the indictment. Prosecutors say that bribes and messages went through Ms. Menendez to the senator.

Mr. Uribe had been charged with seeking the senator’s help to scuttle state insurance fraud investigations that involved Mr. Uribe’s associates. He pleaded guilty in March and agreed to cooperate with the government, admitting in court that he had given a $60,000 Mercedes-Benz to Ms. Menendez to influence the senator.

He was appointed by former President Bill Clinton to the U.S. District Court for the Southern District of New York in 1995. Among the more prominent defendants whose cases he has overseen are Jennifer Shah, a “Real Housewives” star sentenced to 78 months in prison in connection with a telemarketing fraud scheme, and Hassan Nemazee, a major donor to Democratic political causes, who was sentenced to 12 years in a bank fraud case.

Mr. Williams joined the U.S. attorney’s office in 2012 and was named by President Biden to the top post in 2021. He leads an office of 220 assistant U.S. attorneys and executives. He has overseen the prosecutions of defendants like Sam Bankman-Fried, convicted of stealing billions of dollars from his FTX cryptocurrency exchange, and Juan Orlando Hernández, the ex-Honduran president convicted in a cocaine importation case.

She works in the department’s national security division. Ms. Clark helped to prosecute the former high-ranking F.B.I. official Charles McGonigal, who pleaded guilty in a money-laundering case in connection with his work for a Russian oligarch under sanctions.

She helped prosecute 70 current and former employees of the New York City Housing Authority in what the authorities called the “largest single-day bribery takedown in the history of the Justice Department.”

He helped to prosecute defendants in an N.C.A.A. basketball recruiting scandal, as well as a former State Supreme Court justice in an obstruction case.

He helped to prosecute a former Brooklyn assistant district attorney in a bribery case and Robert Hadden, a former Columbia gynecologist who lured patients to his office and abused them.

She helped to prosecute Ghislaine Maxwell, the former companion to Jeffrey Epstein, in a sex trafficking case and Norman Seabrook, the former longtime president of New York City’s correction officers’ union, in a bribery case.

He helped to win the convictions of Sheldon Silver, the former Democratic speaker of the New York State Assembly, and Michael Avenatti, the once high-flying lawyer who tried to extort more than $20 million from the apparel giant Nike.

He previously spent five years as a prosecutor in the U.S. attorney’s office for the Southern District — the same office prosecuting Mr. Menendez. Based in California, Mr. Fee focuses on white-collar criminal defense work.

He spent nearly seven years as a Southern District prosecutor and is now a New York City based partner at the same law firm as Mr. Fee, with an emphasis on complex civil and criminal cases.

A prominent New Jersey defense attorney, he was previously a federal public defender. He also represents Mr. Daibes in the pending bank fraud case in New Jersey.

Previously a prosecutor in the Manhattan district attorney’s office, he now runs his own New York City-based law firm. Last year, he represented Genaro García Luna, Mexico’s former top security official who, after a high-profile federal trial in Brooklyn, was convicted of taking millions of dollars from the Sinaloa drug cartel.