The prospect for a military strike against Iran's nuclear program is now part of the presidential campaign. In yesterday's foreign policy speech, Mitt Romney said the US should side with Israel when it comes to the "red line" for action against Iran's nuclear program. President Obama has said it should be an actual nuclear weapon. But Iran's economy is in serious trouble, partly due to economic sanctions. Will that alter the nuclear program? What do we really know about Iran's capacity or its intentions?