would bring a different kind of life experience, advocacy and ability, the president hopes, to take on some of those tough conservative members of the courts. great to have you. thanks, john. leaders from nearly 50 nations are in washington to discuss how to prevent nuclear weapons from getti inting into hands of terrorists. president obama is hosting the summit, the first to focus exclusively on the threat of unsecured nuclear materials. he is holding a meeting every hour leading up to a big welcoming ceremony this evening, but two leaders not invited. iran and north korea. we ll take an in-depth look at the conference and what leaders expect to aclompish in our second half hour. russian investigators say there were no technical problems with the plane that crashed in heavy fog. officials are trying to learn more about what caused that plane to go down, killing