 This is the president scrambles to contain the defections on Capitol Hill, telling Democrats in a letter he's staying in this race. Adding the question of how to move forward has been well aired for over a week now, and it's time for it to end. So let's bring in Mary Bruce live at the White House tonight. Mary, of course, all eyes on the president again tomorrow when he hosts the NATO summit in Washington. Of course, world leaders will be here. And then on Thursday, a live news conference and a president who says he's staying in this race.