 We really saw a dramatic shift in tone from the president yesterday. He is coming out, not just defiant, but aggressively fighting back, adamant that he is not going anywhere and going a step further, challenging his Democratic doubters, expressing frustration by those in the party who are calling on him to drop out and saying, hey, if any of those guys don't think he should run, he's challenging them to run against him, to go ahead, he said, announce for president.