Sen. John McCain (R-AZ) said on Monday that he "felt a little lonely from time to time" because most of his colleagues did not want to use U.S. military force against President Bashar al-Assad's forces in Syria.

During an interview on MSNBC, host Mika Brzezinski told the Arizona Republican that it seemed like he was standing alone because Congress had been prepared to vote against military strikes and polls showed that Americans were not in favor of taking action.

"You know, it's felt a little lonely from time to time," McCain admitted, pointing out that former President Harry Truman's approval rating sunk down to the 20s during the Korean War.

"If Harry Truman had bowed to public opinion, the world would be a very different place if we lost in Korea," McCain insisted. "There are times when leaders have to stand up. And, frankly, when others have to say what they believe. And if it costs you politically -- as you know, I had some very interesting town hall meetings back in Arizona. But that's what you're supposed to do."

"There's no good options here, but to do nothing, I think, is the worst option. And I hope that we have not sent a message to people all over the world that that -- including our adversaries and bad people -- that we are not willing to do the right thing."

Speaking to NBC News on Sunday, McCain had asserted that that an agreement between the United States and Russia that met President Barack Obama’s goal of securing Syria’s chemical weapons without being drawn into a war was a “loser.”

Watch the video below from MSNBC's Morning Joe, broadcast Sept. 16, 2013.

(h/t: The Hill)