Sen. John McCain appears to have taken a veiled swipe at President Trump while criticizing the practice of draft dodging in an interview aired Sunday. McCain, one of Trump’s most outspoken critics in the GOP, made the comments while speaking about the Vietnam War on an episode of C-SPAN3’s American History TV. “One aspect of the [Vietnam] conflict, by the way, that I will never ever countenance is that we drafted the lowest income level of America, and the highest income level found a doctor that would say that they had a bone spur,” McCain said. “That is wrong. That is wrong. If we are going to ask every American to serve, every American should serve.” McCain, a veteran who was held prisoner and tortured for more than five years in Vietnam, seemed to be referring to an ailment cited as the reason for Trump’s five draft deferments. Trump was reportedly allowed deferments because a doctor said he had heel spurs—calcium buildups in the foot that cause protrusions.