President Obama 's visit first time a sitting president has been ` ` Letterman '' guest . President says he will ask ` ` tough questions '' before sending more troops to Afghanistan . President says he does n't think racism causes opposition to health care overhaul . What did both Malia and Sasha do this summer ? They ` ` time off , '' he says .
President Obama 's visit first time a sitting president has been `` Letterman '' guest . Obama says he 'll ask `` tough questions '' before sending more troops to Afghanistan . President says he does n't think racism fuels opposition to health care overhaul . What did daughters Malia and Sasha do this summer ? They `` goofed off , '' he says .