WASHINGTON, May 2 -- US President Donald Trump's national security adviser (NSA) Mike Waltz is being removed from the post and will be nominated as the country's next ambassador to the United Nations. Secretary of state Marco Rubio will take over the NSA role in the interim, Trump said on Truth Social. Waltz's deputy, Alex Wong, a state department official focused on North Korea in Trump's first term, is also leaving his post. P9...