The Republican and Democratic U.S. senators who have served the longest in the current Senate disagree about whether they should take action on President Barack Obama's nomination for the U.S. Supreme Court.

President Obama nominated Judge Merrick Garland to replace Justice Antonin Scalia, who died in February. Garland is currently an appeals court judge for the District of Columbia.

Both political parties believe the nomination is important because whoever is confirmed will be able to influence the court's decisions. Currently, the court is split: four justices are considered liberal, four are considered conservative.

When Scalia was alive, conservatives won important cases because five conservative justices sat on the court. Republicans are worried -- and Democrats are hopeful -- that Garland will vote with the liberals now on the court.

Patrick Leahy is the senior Democrat on the Senate Judiciary Committee, which examines nominations of federal judges. He has been in the Senate longer than any current senator. He said "we need to do our job" and debate and vote on the nomination.

Orrin Hatch has been in the Senate longer than any current Republican. He is also a member of the Judiciary Committee. He says the Senate does not approve a nominee just because a president wants that person to be on the Supreme Court. He and other Republicans believe Scalia should not be replaced until a new president is sworn in next January. But the Constitution does not limit when in a president's term he or she can make a nomination.

On Tuesday, Hatch said "conducting a heated, divisive confirmation fight in the middle of an ugly presidential election -- and that certainly describes our presidential election season that is well under way -- would do more harm than good."

Hatch spoke at a recent meeting about the Supreme Court nomination, in Washington. At the same meeting, Leahy said "we've had numerous, numerous Supreme Court nominees confirmed in an election year."

The disagreement about whether the Senate should consider a Supreme Court nominee in a presidential election year has caused a debate about what the U.S. Constitution requires the Senate to do.

The document says the president "shall nominate, and by and with the Advice and Consent of the Senate, shall appoint...Judges of the Supreme Court."

Hatch said, "The Constitution gives the Senate the power of advice and consent, but does not specify how the Senate ought to exercise that power. Claims that the Constitution dictates when and how the confirmation process must occur -- immediate committee hearings or timely floor votes -- are false."

Leahy said, "What would be historic is to deny Judge Garland a public hearing and a vote. The Senate has considered controversial nominees. But in every one of those instances, the nominee received a public hearing and a vote."

But Hatch noted that "the Senate has never confirmed a Supreme Court nominee to a vacancy occurring this late in a president's tenure."

Legal experts at the meeting also disagreed on what should take place.

Martin Gold has served as a legal aide to several Republican senators. He said, "The Senate has a duty to consider a nominee, but how it exercises that duty is a matter of dispute. In a sense, [Senate] inaction is also action."

Jeffrey Blattner was a legal aide for Democratic Senator Edward Kennedy, who died in 2009. Blattner noted that, in 1988 – when the Senate was controlled by Democrats – it confirmed Anthony Kennedy to the Supreme Court during Ronald Reagan's last year as president. It was also a presidential election year.

Blattner said, "It did not occur to us [Democrats] ‘Well, it's an election year -- [the 1988 Democratic presidential nominee] Michael Dukakis could win, and we don't have to'" consider the nomination.

People at the meeting agreed that Republicans, who now control the Senate, can refuse for an unlimited period of time to replace a Supreme Court justice who resigns or dies. The Constitution does not limit the amount of time the Senate can take to act on nominations.

But Leahy says considering the nomination, even this late in Barack Obama's presidency, is something the Senate has a duty to do. He said it is also in the best interest of the country.

"We are elected to vote yes or no, not ‘maybe.' You should demand your senators do their job by providing this nominee a public hearing. We are called to fulfill our constitutional duties. We are called to lead," he said.

But Hatch said "the Constitution leaves the judgment to" senators to decide when and how -- or even if -- it should consider a judicial nomination.

A recent public opinion survey found that fewer than half of Americans understand the Senate's role in confirming presidential nominees. Other surveys find that a majority of Americans believe the Senate should at least debate and vote on the nomination of Merrick Garland to be a justice of the Supreme Court.

I'm Christopher Jones-Cruise.

VOA Senate Correspondent Michael Bowman reported this story from Washington. Christopher Jones-Cruise adapted it for VOA Learning English. Kelly Jean Kelly was the editor.