President Obama runs the risks of doing another LBJ : great social programs at home, but a military disaster abroad.
I don't think this violence-prone american society coupled with the industrial-military complex will let him off the hook: the odds are that he will have to escalate the war in Afghanistan, which is doomed to failure.
Like LBJ, he might become a one-term president, unless he's heeding the lessons of history and pull back from both countries in time...and he's great enough to do that.