It's no secret that Donald Trump even has enemies in the Republican Party, and that doesn't appear to be changing anytime soon. One of his most vocal conservative critics has been Sen. John McCain who elaborated on his feelings during a recent interview.

McCain on Trump

Not long after Donald Trump kicked off his campaign for president [VIDEO], he came under fire for a long list of controversial statements. One of the more shocking remarks came when the former host of "The Apprentice" opened up about his feelings on Arizona Sen. John McCain. On McCain's military service, Trump said, "He's not a war hero." Trump claimed that since McCain was captured and made a POW during the Vietnam War that he wasn't a hero, infamously stating, "I like people who weren't captured." As the months went on, McCain never felt comfortable speaking about the president, going as far as threatening to sue him if he tried to reinstate the use of waterboarding and other forms of torture.

Lately, McCain has joined forces with fellow Senator Lindsey Graham in offering constructive criticism of Trump, which continued during a June 11 interview published by The Guardian.

It was just two weeks ago when three Islamic terrorists carried out an act of terror on and around the London Bridge. Multiple deaths were reported, with dozens more left injured after one terrorist plowed through a crowd on the bridge using a truck, while the others took part in a knife attack at a nearby restaurant. In response, Donald Trump was highly critical of London Mayor Sadiq Khan, ripping into him during a series of tweets.

When John McCain spoke to The Guardian about how Donald Trump handled himself in the aftermath of the London attack, the paper described the senator as "visibly irked." "The message is that America doesn’t want to lead," McCain said of the president's actions.

GOP turn on Trump

John McCain then went on to bash Donald Trump for how the rest of the world now views the United States and the country's standing on a global scale. "They are not sure of American leadership, whether it be in Siberia or whether it be in Antarctica," McCain explained. In the most shocking excerpt from the interview, McCain was asked if the United States was better led under Trump or during the Barack Obama administration. In regards to whether the U.S. was better off with Obama in office, McCain replied, "As far as American leadership is concerned, yes."

In addition to John McCain, other Republicans were critical of the president's tweeting habits and the ramifications they are having around the world. "I’ve said a number of times , it’d be easier if Trump wasn’t tweeting so much," GOP Sen.

Jeff Flake admitted. During an interview on CBS News' "Face the Nation" on Sunday morning, Lindsey Graham continued the criticism while elaborating on Donald Trump's Twitter use, stating, "You're your own worst enemy here, Mr. President."