John McCain
In this photo, Committee Chairman Sen. John McCain (R-AZ) listens to testimony during a Senate Armed Services Committee hearing concerning the roles and responsibilities for defending the nation against cyber attacks, on Capitol Hill, Oct. 19, 2017 in Washington, DC. Getty Images / Drew Angerer

Sen. John McCain (R-AZ) was not so subtle while attacking President Donald Trump on Sunday night in regards to his lack of military service. Trump who questioned McCain’s status as a war hero during the 2016 presidential elections, got a taste of his own medicine on Sunday.

In an interview with C-Span about the Vietnam War, McCain pointed fingers at wealthy Americans who were able to get out of being drafted into service. He specifically mentioned the bone spur (a calcium deposit causing a bony protrusion on the underside of the heel bone) deferment that was used, which Trump happened to use for the same purpose.

"One aspect of the 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. That is wrong. That is wrong. If we are going to ask every American to serve, every American should serve," he said.

The Washington Post reported in July 2015, that Trump avoided the possibility of being sent to fight in the Vietnam War by obtaining several deferments so that he could study at Fordham University and the University of Pennsylvania. However, even after completing his education, when Trump was again exposed to the draft, POTUS escaped going to war as he was medically disqualified during the physical examination, according to the ledger from his local Selective Service System draft board in Jamaica, New York, now in the custody of the National Archives.

The reason for his lack of military experience was later explained by Trump during an interview with the New York Times in 2016. "I had a doctor that gave me a letter — a very strong letter on the heels."

The Washington Post report stated that wealthy Americans used bone spurs as a common deferment to avoid getting drafted but for McCain to bring up the ailment in such fashion cannot be considered just a coincidence.

Twitter was quite sharp to react to McCain’s interview. Here are some of the reactions.

Interestingly, this is not the first time that Trump and McCain have tried to condemn each other publicly. In July 2015, during a campaign rally in Arizona, Trump called McCain weak. "We have incompetent politicians, not only the president. I mean, right here, in your own state, you have John McCain."

McCain in response to these comments had then told the New Yorker that what Trump said at his rally had "fired up the crazies" to which Trump tweeted asking McCain to apologize to the crowd that showed up for him.

Since then there have been several instances of McCain and Trump having a go at each other. In October 2016, McCain publicly denounced Trump in a statement and declared that he would not be voting for him after a tape was released which showed Trump making vulgar and misogynistic comments about women in 2005. The tape caused national upheaval just one month before Election Day.

"I have wanted to support the candidate our party nominated. He was not my choice, but as a past nominee, I thought it important I respect the fact that Donald Trump won a majority of the delegates by the rules our party set. But Donald Trump’s behavior this week, concluding with the disclosure of his demeaning comments about women and his boasts about sexual assaults, make it impossible to continue to offer even conditional support for his candidacy. ... Cindy and I will not vote for Donald Trump. I have never voted for a Democratic presidential candidate and we will not vote for Hillary Clinton. We will write in the name of some good conservative Republican who is qualified to be president,"​ McCain's statement read.