Brent Brown never would have imagined that he would be introducing President Barack Obama at an event in Milwaukee. He was a Republican voter, and he had, by his own admission, said some pretty awful things about the president. But when Obamacare literally saved his life, everything changed for him.

“My President, you saved my life, and I am eternally grateful,” Brown wrote in a letter to the president.

Brown had been diagnosed with a medical condition that left him unable to get health insurance, because he had a pre-existing condition....