SPRINGFIELD, Illinois (AP) -- Another clue surfaced Tuesday in the mystery over where Barack Obama will announce his final decision on whether to run for president.

Obama has reserved the Old State Capitol for Feb. 10, the day he plans an announcement, Gov. Rod Blagojevich's office said.

Abraham Lincoln served in the Old State Capitol when he was a state representative. It was the site of his famous "House Divided" speech warning that America could not remain half slave and half free.

If Obama decides to run, making the announcement there would help reinforce his message that America should set aside partisan differences. It would also invite comparisons to Lincoln, another lanky Illinoisan who served in the state legislature and in Congress.

Obama, a Chicago Democrat, was elected to the U.S. Senate in 2004 after serving eight years in the Illinois Senate.

An Obama spokesman refused to comment on whether the campaign has reserved the historic site.