Senators returned to the Capitol in force Monday for the first time since Justice Antonin Scalia’s death injected a heated new issue into this year’s presidential and congressional campaigns. In one of the few chinks in Republicans’ solid opposition to letting President Barack Obama fill the pivotal vacancy, one GOP senator cited a “duty” to vote on a nominee.

Monday’s late afternoon session was coming nine days after the 79-year-old conservative jurist died, leaving the Supreme Court in a precarious 4-4 ideological balance.

Senate Majority Leader Mitch McConnell, R-Ky., has said the president elected this November should nominate the replacement. That assertion that has drawn support from nearly all Republicans and irate, solid opposition from Democrats.

As the two parties girded for what promises to be a months-long battle, 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. “The Senate’s role in providing advice and consent is as important and significant as the president’s role in proposing a nominee.”

Obama is expected to announce his nomination in coming weeks. While McConnell has said he favors “deferring action in the Senate” until the voters have selected a new president, GOP senators will gather on Tuesday for the first time since Scalia’s death to discuss their path forward.

Unanswered questions were making it tough for Republicans to fine-tune their approach just yet, including who Obama will name and who the GOP presidential nominee will be. Another challenge was how GOP senators facing re-election in closely divided states would strike a balance between retaining conservatives’ support and avoiding accusations from independent voters of being too partisan.

One of those senators, Kelly Ayotte, a New Hampshire Republican whose GOP primary election is not until September, displayed no such concerns Friday. She tweeted, “W/ so much on the line, Senate should not proceed w confirmation process until American ppl have spoken by electing a new president in Nov.”

Outnumbered Democrats were solidly behind Obama but seemed to face an uphill climb. They were strategizing over how to maximize pressure on Republican senators, including Ayotte and four others seeking re-election in states Obama won in both 2008 and 2012: Ohio, Illinois, Wisconsin and Pennsylvania.

Sen. Richard Durbin, D-Ill., the No. 2 Senate Democratic leader, said Friday that Republicans “are running the risk that by rejecting any nomination sight unseen, they’re confirming the worst fears of the American people that nothing is being done on the merits. It’s all political.”

Recent decades have seen other pitched battles over Supreme Court selections, including Robert Bork’s 1987 rejection and Samuel Alito’s confirmation in 2006. Yet it’s unusual for the Senate to wage titanic struggles over the selections, or take no action at all.

Since 1789, presidents have sent 160 Supreme Court nominations to the Senate, according to the nonpartisan Congressional Research Service. Of those, 124 were confirmed.

Underscoring the usual lack of controversy, 73 of them won confirmation by voice vote — a method that often indicates that a matter lacks major disagreement.

And of the 51 approved on roll call votes, only 26 times did 10 or more senators vote against the nominee. Since 1967, the Senate has always taken roll calls on Supreme Court nominations.

Of the 36 who failed to win confirmation, the Senate rejected 11 — most recently Bork, in a bitter partisan battle after he’d been nominated by President Ronald Reagan. Thirteen others saw action on the Senate floor that stopped short of a final roll call.

Only 12 nominations have not reached the Senate floor, including just five instances in the 20th and 21st centuries.

Of those 12, six were withdrawn by the president before full Senate action was taken. The most recent was President George W. Bush’s 2005 withdrawal of his nomination of Harriet Miers after some Republicans complained she wasn’t conservative enough.

“The Senate has exhibited little tendency to leave Supreme Court nominations without a final vote simply out of reluctance to act, or to use inaction as an indirect means of denying confirmation,” a 2011 report by the research service said.

(AP)