Justice John Paul Stevens is expected to announce by month's end whether he will retire from the Supreme Court, sources close to him tell CNN.
His departure after nearly 35 years on the bench would give President Barack Obama another opportunity to shape the nation's highest court.
Stevens, who will turn 90 on April 20, has told colleagues he wants to decide soon - for his own peace of mind - but also to give the White House time to select a replacement and for the Senate to confirm the nominee.
He was not on the bench for a brief public session Monday; the court will hold its next public session in two weeks.
Sources close to him suggest he could announce something during this two-week recess, or shortly after the high court's oral arguments end for the term April 28. As of late last month, Stevens had not formally made up his mind, the sources said.
Those sources asked not to be identified because they are not authorized to speak for Stevens, who himself has only hinted at his future.
CNN Senior Legal Analyst Jeffrey Toobin, who interviewed the media-shy justice in early March, is convinced he will leave the court this year. "The fact that he's given interviews to me and others, which is also very out of character for him, suggests that this is part of a leave-taking operation," Toobin said.
But several close friends suggest Stevens may wish to stay for another year, and several former law clerks have privately encouraged him to do just that.
Sen. Arlen Specter, D-Pennsylvania, a member of the Judiciary Committee that would hold confirmation hearings for any replacement, urged Stevens to delay his exit.
"I think the gridlock in the Senate might well produce a filibuster, which would tie up the Senate on a Supreme Court nominee," Specter told Fox News Sunday. "I think if a year passes, there's a much better chance we can come to a consensus."
Speculation over Stevens has increased since he confirmed last fall he had hired only one law clerk for the next court term, which begins in October. Sitting justices can hire four law clerks, while retired members only get one.
The White House has quietly but actively prepared for weeks in anticipation of a vacancy, government sources told CNN. Top officials have no specific information that Stevens or even another justice will retire after the court's session ends in late June, but want to be ready, those sources emphasized.