ASUNCION, Paraguay — Paraguay's President Horacio Cartes on Wednesday suffered at least a temporary a setback in his effort to take up a Senate seat once his term ends after his opponents boycotted a congressional session on his resignation.

The lack of a quorum blocked a vote on Cartes' request to step down, which he wanted to do assume the Senate seat he won in the April 22 general elections. He ran while he was still president.

Under Paraguay's Constitution, after leaving office presidents become senators for life but it is a symbolic position in which they wield no power. Cartes wants to take up a Senate seat with full rights because he won the seat in an election, and extend his political influence in this way.

His terms as president ends in August, but he needs to leave office by June 30 to be sworn in with other senators because Paraguay's constitution says he can't hold two offices at once.

Some experts argue that a delay in getting into the Senate would eliminate his immediate chance of a leadership position. Failure to get in could also open him to potential prosecution on corruption allegations. But analysts say Cartes still has plenty of time before the deadline to win enough votes.

Before taking office in 2013, Cartes amassed a fortune with companies in industries that ranged from banking to tobacco to soft drinks to soccer, which made it difficult to make a move as president without generating complaints of conflicts of interest.

President-elect Mario Abdo Benitez, who is also a member of Paraguay's ruling Colorado Party, takes office on Aug. 15. Lawmakers begin congressional sessions on July 1.

But the admittance of Cartes and former President Nicanor Duarte to Congress will not be automatic if most lawmakers consider that they should be senators for life, with a voice but without a vote, as the Constitution states.

The Supreme Court had approved the candidacy of both former leaders to run for a Congressional seat earlier. But opposition senators, including dissident lawmakers from the ruling Colorado party, reject this. They say that the Constitution must be followed.