Speaking at a White House news conference, Obama also responded to criticism from Republican presidential candidates who say he's been weak on Iran. Obama says presidential candidates don't have "a lot of responsibility" and are not commander in chief.
Obama says the GOP is talking about war in a casual way. He says if his opponents want to launch a war with Iran, they should explain the consequences to the American people.
He reiterates his comments from earlier this week - that his policy on Iran is not one of containment, but of stopping Tehran from acquiring a nuclear weapon.