Senator John McCain told that he had one piece of advice for those who seek positions of leaderships: be a proponent only of things you truly believe in.

"Every time in my career that I've done something for political expediency, I've later regretted it. When I've taken on an issue with my true beliefs, even if it's unpopular at the time, it always turned out right in the end," he revealed.

While McCain was running for the Republican nomination for president in 2000, the South Carolina State Senate passed a bill to remove the Confederate flag from the top of the State House dome.

Because he thought it would gain him votes, McCain went against his true values on the matter, saying he thought it was a state's issue.

"This was clearly a cowardly approach, and in the end, I lost regardless and displayed cowardice," he insisted. "You can do things that appear beneficial, and they may give you temporary advancement or movement along your path, but unless it's something you really believe in, you'll never succeed."

Watch the video version of my interview with Senator John McCain: