This is why Donald Trump has been invincible — and why he might not be invincible much longer

Republican presidential candidate Donald Trump gives a thumbs up after giving a foreign policy speech at the Mayflower Hotel in Washington, Wednesday, April 27, 2016. Trump's highly anticipated foreign policy speech Wednesday will test whether the Republican presidential front-runner, known for his raucous rallies and eyebrow-raising statements, can present a more presidential persona as he works to unite the GOP establishment behind him. (AP Photo/) (Credit: AP/Evan Vucci)
Remember Dennis Rodma