Obama to announce return of 30,000 troops from Afghanistan by end of next year

President Obama's "surge" of 30,000 troops to Afghanistan announced in late 2009 was meant to be temporary, and Wednesday night the president is expected to announce that they will return home by around the time voters head to the polls to determine whether he gets another term.

In prime-time speech to the nation, Obama is expected to say about 5,000 troops will begin coming home this summer with an additional 5,000 troops by the end of this year, sources told CBS News. And about 20,000 more troops are expected to return to the United States by the end of 2012, the sources said. That would still leave about 70,000 troops in Afghanistan -- about twice as many troops as when Obama took office in January 2009.

That timetable is more aggressive than some military advisers had urged. Obama made the final decision Tuesday after weighing options presented to him by General David Petraeus, his top commander in Afghanistan.

Some military advisers feared a rapid withdrawal could put at risk some of the gains made against the Taliban.

Senate Armed Services Committee Chairman Carl Levin (D-Mich.), on the other hand, echoed a sentiment of many on Capitol Hill when he told reporters Tuesday that "the notable improvement in the security situation" in Afghanistan allows "for a reduction of at least 15,000 U.S. troops by the end of this year."

Vice President Joe Biden has also reportedly urged for a faster troop withdrawal and said last December that the drawdown would start "in July 2011 and we are going to be totally out of there, come hell or high water, by 2014."

A recent CBS News poll showed that 64 percent of Americans now want the number of troops in Afghanistan decreased. The United States has spent $120 billion on the war this year alone.