Fifteen former American Bar Association presidents wrote Senate leaders Tuesday demanding that they vote and confirm Judge Merrick Garland to the Supreme Court.

"Ladies and gentlemen, please do your jobs," Dennis Archer, who led the ABA from 2003-04, urged lawmakers during a conference call organized by the White House.

Noting activists' efforts to push the Senate, Martha Barnett, who led the group from 2000-01, said Senate Republicans can expect to see "a different kind of action" once voters realize the Supreme Court's docket is full of cases on a range of issues affecting all Americans.

"The stated refusal to fill the ninth seat of the Supreme Court injects a degree of politics into the judicial branch that materially hampers the effective operation of our nation's highest court and the lower courts over which it presides," the group wrote.

They countered Republicans' argument that it is too close to a presidential election to consider Garland, chief judge of the U.S. Court of Appeals for the District of Columbia Circuit.

"There is no election year exception" in the Constitution, they wrote. "[T]hroughout American history, presidents have nominated individuals to fill vacancies during the last year of their terms. Since the 1900s, six justices have been confirmed in presidential election years."

The trio of lawyers on the conference call all pointed out that a Democratic-led Senate approved a Republican president's Supreme Court nominee as recently as 1988, a presidential election year.

Senate Judiciary Chairman Chuck Grassley, R-Iowa, told Garland on Tuesday that the GOP will not consider his nomination until "the people have spoken," but the former ABA leaders on the conference call noted that "the people have already spoken" when they elected Obama in 2008 and re-elected him in 2012.

"If the Senate continues to refuse to follow the appointment process for the purpose of allowing the next president to nominate a Supreme Court Justice, the court will be forced to operate with only eight members for an unprecedented two terms," the 15 lawyers wrote.

"A vacancy on the highest court in the land can result in split 4­-4 decisions, which can leave inconsistencies among lower courts unresolved and different rulings on federal law throughout the country unsettled," they warned.