There was very strong support for Gates among Democrats, said one Democratic source in the Senate whose boss was intimately involved in bringing Obama and Gates together to see if they were compatible. Obama's decision to keep Gates follows speculation, encouraged before the election by Obama's aides, that Gates would stay on for an interim period. A registered independent, Gates has served various Republican administrations. President Bush nominated Gates to replace Donald Rumsfeld after the 2006 midterm elections, when the war in Iraq was descending into chaos and became a political liability for Republicans.
Gates will continue to preside over two US wars, in Iraq and Afghanistan that Bush launched as part of the larger war on terror.
There are several issues on which Gates and Obama disagree, including missile defense. Gates supports placing a missile defense system in Europe, but Obama already has suggested that he won't sign off on it until the technology has been proven capable.
A formal announcement is expected immediately after the Thanksgiving holiday weekend.