On Monday, President Donald Trump announced his pick for his second National Security Adviser: Lieutenant General H.R. McMaster. Gen. McMaster joins the White House national security team after Gen. Michael Flynn resigned after only 24 days. "He is a man of tremendous talent and tremendous experience," the president said of McMaster. "I watched and read a lot over the last two days. He is highly respected by everybody in the military, and we're very honored to have him."