U.S. decision on joint military exercises with South Korea "very reversible," Winnefeld says
CBS News military and homeland security analyst Sandy Winnefeld, a retired Navy admiral and former vice chairman of the Joint Chiefs of Staff, joins "CBS This Morning" to discuss Tuesday's historic summit between President Trump and North Korean leader Kim Jong Un. He says he's "cautiously optimistic" and weighs in on the halt of joint military exercises with South Korea. He also says it would be "wise" to keep U.S. military presence on the Korean Peninsula.