Senate Republican leaders Monday seized on comments made by Vice President Joe Biden 24 years ago, when the then-senator from Delaware said the Senate should not consider a Supreme Court nominee during an election year.

"Once the political season is underway and it is, action on a Supreme Court nomination must be put off until after the election campaign is over," Biden said in June 1992 on the Senate floor, according to a C-SPAN recording of his remarks.

Biden was referring to a hypothetical situation, since the Senate was not considering a nominee at the time of his remarks. But the sudden death of Justice Antonin Scalia earlier this month has left a precarious 4-4 ideological balance between right- and left-leaning justices as they consider cases on abortion, voting rights, Obama's health care law and other polarizing issues. 

Senate Majority Leader Mitch McConnell, R-Ky., reiterated the stance he took hours after Scalia's death that the next president should select a court nominee. He said Senate Judiciary Committee Chairman Charles Grassley, R-Iowa, whose statements have wavered, agreed with him.

But separately, McConnell's press office and Grassley in a floor speech went further and cited the 1992 Biden remarks. Grassley called the comments "The Biden Rules" and said the vice president "knows what the Senate should do."

Biden defended himself in a written statement, saying that in his 1992 speech he said the Senate and White House should cooperate "to ensure the court functions as the founding fathers intended." He said under his long-time leadership of the Senate Judiciary Committee, the chamber considered nine Supreme Court nominees "and the current Senate has a constitutional duty to do the same."

Both sides have spent days unearthing comments members of the other party made about court nominations years ago under presidents of different parties when the political circumstances were reversed.

McConnell's assertion that the president elected this November should nominate the replacement has drawn support from nearly all Republicans and irate, solid opposition from Democrats. Yet as the two parties girded for what promises to be a months-long battle, some cracks have appeared on the GOP side.

Sen. Mark Kirk, R-Ill. — who faces a difficult re-election race this year in a Democratic-leaning state — distributed an opinion column he'd written for the Chicago Sun-Times saying he looks forward to Obama selecting a nominee.

"I also recognize my duty as a senator to either vote in support or opposition to that nominee following a fair and thorough hearing along with a complete and transparent release of all requested information," Kirk wrote.

Sen. Susan Collins, R-Maine, said she favored Judiciary Committee hearings "so that there can be an in-depth vetting of the nominee and his or her views." Several other GOP senators said they'd defer to a decision by Grassley about holding hearings, including Sens. Richard Burr, R-N.C., Rob Portman, R-Ohio and Ron Johnson, R-Wis., who face re-election contests in November.

Obama is expected to announce his nomination in coming weeks. GOP senators will gather on Tuesday for the first time since Scalia's death to discuss their path forward.

The Associated Press contributed to this report.