A federal jury has deadlocked in the corruption case against Sen. Robert Menendez (D-N.J.), but the judge has ordered jurors to return Tuesday morning to further deliberate.
Menendez is being tried on 12 counts of corruption, including bribery. The trial is in its 11th week.
Menendez could face up to 20 years in prison on the most serious charge.
Federal prosecutors argued in the Newark, New Jersey, courtroom that Menendez, 63, was the "personal senator" to Florida ophthalmologist Dr. Salomon Melgen, according to NBC News.
Melgen was found guilty in April of Medicare fraud.
Prosecutors allege the misconduct occurred between 2006 and 2013, during which Menendez took several trips to the Dominican Republic on Melgen's private jet.
They say that in exchange for the trips, Menendez helped obtain visas for several of Melgen's girlfriends. Federal prosecutors also said Menendez was bribed to lobby the State Department on Melgen's behalf regarding a $500 million port security contract in the Dominican Republic.
If Menendez is convicted, he would not have to leave the U.S. Senate. But in 2008, Democrats said the late Sen. Ted Stevens (R-Alaska) should resign if convicted. Stevens lost re-election that year.
The Senate Democrats, now with a 48-seat minority, are nervous about the situation. Earlier this month, a statement from former Senate Democratic leader Harry Reid, that "a convicted felon is not going to be able to serve in the United States Senate," was removed from the Senate Democrats' website.
Meanwhile, the jury has had problems. Last week, U.S. Judge William Walls dismissed juror Evelyn Arroyo-Maultsby for a vacation. Arroyo-Maultsby told the press after she left that she believed Menendez was innocent on all charges.
Jurors also asked Walls for the definition of a senator, according to Fox News. Walls did not give them an answer.
If the jury deadlocks for good and a mistrial is declared, federal prosecutors have the option to retry the case.