Why is obama only bringing back 30,000 troops from afganistan and leaving the other 70k there to fight?

were back to round 1 to pre-surge troop levels, they mention there going to bring the other 70,000 back somewhere in 2014 and well have a new adminisrtation before then so who knows what will happen, the troops will be comming back right before the elections, does it smell like a scam for extra votes. a href="http://news.yahoo.com/s/ap/20110622/ap_on_go_pr_wh/us_us_afghanistan"http://news.yahoo.com/s/ap/20110622/ap_o…/a