I’ll never forget the time the McCain delegation stopped in Budapest in 2014 on the way to a conference in Munich. We only spent five hours on the ground. But John McCain accomplished more diplomacy, human rights advocacy and mischief in those five hours than most senators do in a month. This was why folks traveling with McCain referred to his trips as “Bataan death marches,” a torture-themed joke McCain thought was funny.

That day he met with Hungarian opposition leaders, heard them out about Hungary’s slide into autocracy and promised that Americans were watching. He then met with Prime Minister Viktor Orban, scolded him for his autocratic moves and said America was watching. Both sides got the message. On the way out, McCain apologized to the Hungarian officials: he felt that President Barack Obama had made a mistake by sending someone he thought was a supremely unqualified ambassador.

Just as a joke, McCain kept introducing delegation member Rep. Adam Kinzinger (R-Ill.) as “Henry Kissinger’s grandson.” The Hungarians didn’t know it was a joke, but McCain thought it was hilarious. So did I. Kinzinger was one of many young lawmakers McCain was recruiting for his lifelong mission of traveling anywhere he thought America’s presence was needed to speak truth to dictators or give voice to the oppressed. Sometimes it was just a matter of showing up in order to find out what was going on.

Before sunset, McCain was on to the next stop. That was a typical McCain visit: a mix of rogue foreign policy, robust defense of U.S. values and humor. And that was John McCain: relentless, principled, honest, funny and dragging along anyone who could keep up.

“If I learned one thing from John it’s that you cannot protect America sitting in Washington,” McCain’s favorite travel buddy, Sen. Lindsey Graham (R-S.C.), told me. “You can’t learn how this world works watching cable news.”

The pair traveled to active war zones in Iraq and Afghanistan 47 times, Graham said, because McCain wanted to see for himself what was true and what was not. He wanted to talk to the soldiers. He had the stature, knowledge and gumption to call out the generals when necessary.

“John would tell you what you didn’t want to hear because he knew that the consequences of ignoring it were going to be great,” said Graham. “If I were a president, I would listen to John McCain because he busted his ass to get that information.”

According to Graham, McCain’s favorite thing to do in life – aside from visiting far-off countries and getting shot at — was playing craps. McCain loved constant action and being in the fray – and he never really stopped. Even on the long plane rides from one country to the next, he would read books voraciously, and he wanted to discuss them with whomever was also awake.

“The North Vietnamese missed an opportunity. The way to torture John McCain would have been to put him on a cruise ship with only the shopping channel and no books,” said Graham. “He would have sung like a canary.”

McCain’s mentors — such as Mo Udall, John Tower and Henry M. “Scoop” Jackson — taught him about the impact that one senator can have on the lives of the oppressed around the world. In return, he felt that it was his duty to mentor a new generation of leaders, former senator Kelly Ayotte told me.

“He was always our conscience,” she said. “He always understood and was able to articulate America’s role in the world and what America stood for.”

I personally witnessed McCain defend U.S. interests and values in far-off places such as Bahrain, Tunisia, Singapore and Serbia. He showed up at countless international conferences to speak about U.S. policy, including an annual forum in Canada where he always gave the keynote dinner speech, which McCain turned into a comedy routine. I came to know the jokes by heart.

“After I lost the 2008 presidential election, I slept like a baby … sleep for two hours, wake up and cry, sleep for two hours, wake up and cry.”

“What was so funny was not the jokes themselves but the fact that he told them over and over again,” said Graham.

You knew McCain liked you when he started insulting you to your face. When I asked him a question in public, he would often stop and announce to the room, “This is Josh Rogin, the worst journalist in Washington.” When I first introduced him to my then-fiancee (now my wife), he told her, “There’s still time, it’s not too late to change your mind.”

And yet on every trip, McCain would always take the time to meet with the people whose voices were not being heard. He saw America’s role abroad as defending not only Americans but also the rights of all people struggling for self-determination and basic dignity.

Thanks to his foresight in training the next generation of leaders, his international fight for freedom will survive long after he is gone.

“Here’s the bad news for dictators and despots and thugs,” Graham said. “There’s a whole army of McCain-ites coming.”

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