Washington (CNN) -- 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 Obama another opportunity to shape the nation's highest court.

Stevens, who turns 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.