Senator John Kerry says President George W. Bush should bring home 20,000 troops from Iraq over the Christmas holidays if the December parliamentary elections there are successful. Defeated by Bush last year and a potential candidate for the Democratic presidential nomination in 2008, Kerry called for a "reasonable time frame" for pulling back troops rather than a full-scale withdrawal advocated by some Democrats. He said it could be completed in 12 to 15 months. "It will be hard for this administration, but it is essential to acknowledge that the insurgency will not be defeated unless our troop levels are drawn down ... starting immediately after successful elections in December," Kerry said in a speech Wednesday at Georgetown University. The presence of 159,000 US troops in Iraq is deterring peace efforts, said Kerry, a member of the Senate Foreign Relations Committee.