NEW YORK (Reuters) - Jury selection is expected to begin on Monday in the corruption trial of U.S. Senator Robert Menendez, a case that could affect the Democrat's reelection prospects and help determine which party controls the Senate next year.

Menendez, 70, and two New Jersey businessmen face charges in a bribery conspiracy case in Manhattan federal court, in a trial that could last five to eight weeks. The senator's wife, Nadine Menendez, has also been charged but will be tried separately.

All four have pleaded not guilty.

Menendez, New Jersey's senior senator, is up for re-election in November and if exonerated hopes to run for a fourth full term as an independent.

But recent polls show Menendez is deeply unpopular among New Jersey voters, and many Democratic senators including New Jersey's Cory Booker have called for him to resign. Democrats and independents who caucus with them hold a 51-49 Senate majority.

Prosecutors said the Menendezes accepted cash, gold bars and a Mercedes-Benz convertible in exchange for the senator wielding his political influence in New Jersey and to help Egypt's and Qatar's governments.

The senator allegedly promised to help Egypt obtain arms sales and other military aid, and helped defendant Wael Hana, an Egyptian American businessman, obtain a lucrative monopoly on the certification of halal meat exports to Egypt.

Prosecutors also said Menendez tried to help defendant Fred Daibes, a prominent New Jersey developer, obtain millions of dollars from an investment fund linked to Qatar's government, and sought to disrupt a federal criminal case against Daibes in New Jersey.

Menendez and his wife also face obstruction of justice charges. The alleged crimes occurred between 2018 and 2023.

A fifth defendant, Jose Uribe, pleaded guilty to bribery and fraud charges in March and agreed to cooperate with prosecutors.

MULTIPLE TRIALS

Nadine Menendez's trial is scheduled for July 8. Her case was separated after her lawyers said she developed a serious medical condition that required a lengthy recovery.

Documents released last month showed that Robert Menendez, if he chose to testify, might blame his wife by disclosing marital communications that would "tend to exonerate" him but could incriminate her.

His lawyers said Menendez could explain what they discussed during dinners with Egyptian officials and offer his wife's explanation for why Hana and Uribe "provided her certain monetary items."

The senator's corruption trial is his second.

In 2017, a New Jersey federal judge declared a mistrial after jurors deadlocked on whether Menendez broke the law by providing help to a wealthy ophthalmologist, Salomon Melgen, in exchange for lavish gifts and political contributions.

Menendez became a senator in 2006. He had chaired the powerful Senate Foreign Relations Committee but stepped down last September after first being indicted.

Several other current and former members of Congress also face federal criminal charges, including Representative Henry Cuellar, a Texas Democrat, and former representative George Santos, a New York Republican.

While New Jersey's voting population leans Democratic, public support for Menendez collapsed following his indictment.

Fewer than one in six voters polled in March by Monmouth University and Emerson College Polling/PIX11/The Hill said they approved of Menendez's job performance. Even fewer said they would vote for him as an independent.

Several Senate seats held by Democrats or independents may be closely contested in November. A seat now held by West Virginia Democrat Joe Manchin, who is not seeking reelection, is expected to turn Republican.

(Reporting by Jonathan Stempel in New York; Editing by Noeleen Walder and Diane Craft)