Sen. Rand Paul is backing calls for an international investigation of the U.S. military afteran Afghan hospital last Saturday.The strike on the Doctors Without Borders-run facility killed 22 people, and has triggered calls from the medical charity for anThe Kentucky Republican, a GOP presidential candidate, says he could support that."I don't mind an outside international investigation," he tellsBut he pressed a more isolationist approach in Afghanistan, saying the original mission after 9/11 is "long gone.""[S]omebody needs to step up and say why are we there and what is the policy" in Afghanistan, he said."Doctors and hospitals should never be targeted, and so that is completely unacceptable," said Paul. "But if it is an accident, it is still bad policy, because why are we dropping bombs in Afghanistan?"There's not a clear-cut U.S. role," he argues. "We should not be in perpetual war all over the world."