On May 15, 2007, at a Republican primary debate in Columbia, South Carolina, longshot presidential candidate Ron Paul shocked the room with his answer to a question about how 9/11 changed America: "Have you ever read the reasons they attacked us? They attack us because we've been over there; we've been bombing Iraq for 10 years."

Then-frontrunner Rudolph Giuliani, visibly agitated, interrupted the proceedings to condemn Paul's "extraordinary statement…that we invited the attack because we were attacking Iraq" and then demand a retraction as the crowd went wild. Campaign reporters, straight and ideological alike, started writing Ron Paul's obituary. Politico Executive Editor Jim VandeHei, on CNN's American Morning the next day, said that "Rudy Giuliani came off terrific…mostly because he got that softball, where Ron Paul lobs it to him and basically blames the U.S. for the 9/11 attacks…You dream of those moments when you're a candidate, that's for sure." Conservative radio host Hugh Hewitt agitated for Paul to be barred from future GOP debates. National Review's headline captured the media zeitgeist succinctly: "Giuliani Up, McCain Up, Romney Down, and Ron Paul Out—Way Out."

But a funny thing happened on the way to Paul's seemingly inevitable ostracism from the Republican Party for the sin of noninterventionism: His star began to rise, while Giuliani's crashed and burned. Not only would the rambling septuagenarian outpace the famous former New York mayor in both delegates and the popular vote during the 2008 campaign, his message of peace and American pullback electrified a new generation of activists and voters, while Giuliani's hawkish stance has become less popular by the day.

Now retired from Congress after a second, more successful run at the White House, Paul can gaze out at a world and a GOP that has become much more sympathetic to his once-lonely view of the world. His son, Sen. Rand Paul (R-Ky.), has been hanging out near the top of the polls for the 2016 presidential race, selling a more Republican-friendly version of intervention-skepticism. There are entire armies of young libertarian activists—including many recent military veterans—who got their introduction to the philosophy through Ron Paul's bracing criticism of U.S. misadventures abroad. You can't talk about libertarian foreign policy without talking about—and to—Ron Paul. reason Editor in Chief Matt Welch caught up with the three-time presidential candidate over the phone in October.

reason: What should we be doing with our foreign policy? How should we approach the world?

Ron Paul: We certainly had some good advice in our early history, and we haven't followed it. Whether it was Washington or Jefferson, they generally talked about a foreign policy of staying out of the internal affairs of other nations and staying out of entangling alliances. That's 100 percent opposite of what we do.

But on the very positive side, [their advice] was to set an example and have a country that defended liberty, and maybe others would want to follow us. As far as dealing with other nations, it was to strive for peace. The best way to achieve that would be through commerce, through trade. So they were strong believers in that, and I am too.

We're so much better off now with China than we were when I was in high school and we were killing each other. Hopefully we don't drift back into that kind of thing with China.

Those would be the goals that are very, very positive. Along with the moral and constitutional right and obligation for us to have a strong national defense to defend our security, but never to use it to go around the world looking for monsters to destroy, which has been driving our foreign policy, especially these last 15 or 20 years. It just seems like if we don't have somebody, we have to go looking for them. I think that is a policy of disaster, and it's going to bankrupt our country. The policies always fail.

reason: You mention monsters—there are monsters in the world, for sure. Whether they are exactly as Washington defines at any given moment is perhaps a separate question. But there are moments when a dictator or a group is committing genocide. What is the role of a U.S. foreign policy in a world with monsters?

Ron Paul: Well, if you know they are monsters, you shouldn't help them, you shouldn't ally yourself with them. That would not be an honest friendship.

If you have a monster like Stalin, who had killed hundreds of millions of people through all methods and [with] what that system did, it would hardly be good advice to say, well, become close military allies, and then divide up the world between the West and the East and have a Cold War for 50 years.

You don't become an ally to them, but neither do you decide that you can change the monsters of the world. Because there are some in every country, and there are some in this country. Our obligations are to deal with some of the warmongers we have here and the infractions of our liberties here at home. But there is no moral obligation, there's no constitutional authority, and there's no practical advantage for us [to go abroad]….We shouldn't be an ally of the Soviets, but we're not going to invade them either.

So that's a big difference from what we do. Either we're close allies with the monsters or then we turn on them and throw them out and put a new monster in place. It's a policy of insanity.

reason: Is there something that the United States and/or the international community should do proactively in response to one country basically gobbling up another one? This is the initial Gulf War scenario: Iraq invades Kuwait. Take the U.S. and its backing of Iraq out of that for a second—should there be some kind of response? What do you do when one country gobbles up another?

Ron Paul: You learn your lesson and you learn not to encourage this. Because actually we had been a close ally with Saddam Hussein. We encouraged him to invade Iran, and he saw that we were friends and did a deal. So then he suggests that he might go into Kuwait and gets a green light from our administrators. I would say that's how you prevent these things from happening.

But once it happens, it's not in our self-interest to sacrifice a lot of American lives to go over and start a war that's still going on. It started in 1990 and here we are 24 years later and we're still fighting this same war? Maybe there would be a balance of power over there right now if we wouldn't have been involved. We're still fighting World War I over there. Those lines are artificial. Who says that there's something sacred about Kuwait? The lines were drawn up by Europeans and maybe some people had a beef about it.

But I think the worst thing to do is to go over there and sacrifice life—American lives—getting involved in a threat that is not a threat to us. It's a threat to them, the instability of that region. That's not our responsibility and things have been made much worse by us assuming that responsibility.

reason: Is there a U.S. intervention after World War II that you think retrospectively was a good idea?

Ron Paul: Not really. And even if I thought so, it was not done properly. If we got involved militarily, I think there should've been a declaration of war.

I was very much aware of the Cold War, and was drafted when the missiles were found in Cuba. The thought crossed my mind—and this is not a conclusive thought—[that] maybe what a president ought to do under these circumstances is say: Don't expand the war in Vietnam without congressional approval of war, [but] maybe doing something with Cuba made more sense for our national security. Right on our borders and nuclear weapons on our borders; you could make a case for that. I'm glad they didn't do it; I probably would not have supported it. But in comparison, that made a lot more sense.

But for the rest of the stuff that went on over all those years—Vietnam, Korea, everything in Lebanon and the Middle East and even Grenada, going into South America, going into Panama, and continuing the fight with Cuba that was so unnecessary and actually solidified the power of the Castros—I would say that military interventions by the United States after World War II were all unjustified. Had they been justified, they should have been done precisely through the Congress and not a president just arbitrarily starting these wars.

reason: What about the post-9/11, failed-state-that-gives-harbor-to-people-who-attack-us model? Which might be coming up again with ISIS, depending on how that all turns out. But certainly in Afghanistan—although right now it's the least popular war in history and deservedly so. But in an ideal scenario, what militarily do you do when a lousy or a failed state harbors people who then attack the U.S.?

Ron Paul: Well, I don't think the government of Afghanistan attacked us. Yes, it is true that Al Qaeda traveled through there, but they did a lot of training in Germany and Spain and southern Florida in order to attack us here on our homeland.

But you still have to contend with this. I could make a case for the stupidity of World War II by pointing to the stupidity of World War I, but that doesn't answer the question, "What do you do after Pearl Harbor?" You have to retaliate even though we are a contributing factor to the ongoing war. I would say we had to do something.

The authority to go after those individuals precisely responsible, I voted for that. So I guess that might be the exception to what I said earlier. It was a reluctant support, at least to go after those particular individuals. But I also was struggling with that, because that is when I came up with trying to revitalize the concept of a letter of marque and reprisal in order to limit our problems. Because it wasn't a country, it wasn't the whole world, we weren't about to be truly invaded. We had a problem—regardless of how it was created—that maybe by targeting an individual, we might've gotten him very early on. We knew where bin Laden was and it looked like they could've gotten him, but it went on for years and years after that. I think that was a worthwhile thought, but of course no one was interested.

reason: So you think that would be a decent model going forward, instead of the 30-year war that we are apparently now launching in the broader Islamic world?

Ron Paul: I think it would be much better. The big question is what is the practicality of it? The Congress is supposed to write the letter of marque and reprisal. But I think it was easier to target a small group of people—and I do believe it was a small group of people because they couldn't have kept 9/11 secret unless it was a very, very close-knit group. The real conspirators on that all got killed, so there were a lot less [to track down].

Now we have a phenomenon going on that is a pervasive phenomenon. Just recently in a 16-day period there were 350 villages overrun in Iraq. Well, there aren't that many ISIS members. That means there's something wrong with the villagers and the people and the governments. Think of the millions and millions of people who claim they hate ISIS. So there must have been some token support. It's sort of a philosophic thing; they're getting a consensus, and to me, I'd have trouble writing the letter of marque and reprisal. It would be different because it's not a 9/11 attack. On 9/11 they bombed our cities. It'd be a lot easier to deal with that by writing a letter because there's the downside of our war in Iraq.

We're seeing all the unintended consequences, all the blowback. Supporting [an Iraqi] government is a total failure. So I think the conditions wouldn't be the same. But I think if you had to go one way or the other, a 30-year war shouldn't be the way to go. And I just think that any time we get involved there it really helps the enemy more than it helps us.

reason: In a Ron Paul universe, would NATO [the North Atlantic Treaty Organization] exist?

Ron Paul: No. I sort of go along with Robert Taft on that one—and Robert Taft wasn't exactly an individual who was an absolutist. He saw this as impractical. His tendencies were for nonintervention, so he thought NATO would commit us to more involvement than need be. Look, NATO is involved in Ukraine. Afghanistan was a NATO war and NATO was involved with Libya. But all that is a cover for us. We're NATO. When NATO votes to go in, who pays and where do the weapons come from and who makes the money? It's our weapons producers that make all the money.

reason: Without a NATO, without the current system with America assuming a hegemonic superpower role, if you withdraw all troops from Japan and Korea overnight—which is something that you and I would probably enjoy watching—one would expect that one of the reactions would be that China would say, "Great!" and flex its power more. If we disbanded NATO tomorrow, Russians would be high-fiving each other in the Kremlin and the Baltics would wonder if they're going to survive. What do you think the world would look like and how do you think other actors would act in the face of an American retreat from its role right now?

Ron Paul: There's a little bit of guesswork on how they'd react. But you can go by the history and [conclude] they may act a lot better.

When we're pounding on their borders, when NATO is on the borders of Russia, maybe their reaction is very logical. Once the Soviet system collapsed and we backed off, they started trading. That's why so much trading is going on there. Maybe that would have continued and expanded. That's what I think would have happened.

China doesn't have a history of wanting to have a world empire, but I think because they get pushed, and we go over there and assume that we have control over all the sea lanes over there and that we're going to be involved in their affairs. I don't think China has the history of expansion.

It's the same way with the Iranians. They don't have [that history], yet they're probably top of the list right now of our enemies. They do not have a history [of expansion] unless you go back maybe a thousand years, at least hundreds of years.

So I think the assumption that all of a sudden Russia and China are going to take over—what we ought to look at is [that] they may well take over financially. We're setting the stage for the disintegration of the West, the financial empire, the disintegration of the dollar as the reserve currency of the world.

If people are worrying about a powerhouse, they ought to worry about our policies now in Ukraine, which are insanely driving wedges between the East and West. They're going to get annoyed enough that they would just love to see us go down, and we're not in the driver's seat. We have the debt and they have the money in the bank. It's exactly opposite of what it was like at the end of World War II.

reason: Do you think that American foreign policy basically post–World War II has overall been a force for good and peace?

Ron Paul: There's a mixed bag. The governments have not been a force for peace, but there's something pretty neat happening in the states. The governments themselves are losing credibility, [but] the people are more likely to speak out. The governments are still as anxious to have wars as ever before for their various reasons, the commercial reasons and who knows what else; at the same time, I see their power weakening and the people speaking out.

For instance, the other day they polled the military and it was something like 72 percent of our military said, "Don't go in [to Iraq and Syria] with boots on the ground." Maybe reason recognized it, but where I got the support during the last campaign came from the military. My top three donors were [members of] the Air Force, the Army, and the Navy. Of course, for my opponent the top three were banks. I always thought that would've been interesting news, but that got by the media.

reason: Whenever reason opens its doors in D.C., we frequently have members of the military who are passing through or taking 12 months in Washington in between tours. They will come over and say, in a very intense way, "I came to libertarianism because I saw what happened over there and I started listening to Ron Paul." It's a great, unremarked-on source of new libertarians out there.

Ron Paul: I don't know if I can claim any credit, but if it's true I would feel good that I was able to get some people to think differently and not be ashamed of it.

It's been drilled into us that if you're not for these wars, that means you're not for the military, you're not for the Constitution, you're not for defending liberty, and all these things. Yet because there weren't enough libertarians and conservatives to take this [anti-war] position—it was always the wild-eyed Jane Fonda liberal left, they didn't have the credibility and it was easier to attack. Today, though, it's left up to us to defend this and make people feel good so we can win more converts. We don't want to chase the progressives away, and that's why I like to talk to Dennis Kucinich and Ralph Nader and these people, and I hope that the progressives will stick with this. At the same time, I think manning the fort of a less aggressive foreign policy is coming more from the constitutional conservatives and the libertarians.

reason: Speaking of which, there's an interesting [former Rand Paul and Ron Paul adviser] Jesse Benton quote in The New Yorker recently where he says, "If Ron were president, he would have had to govern like Rand. Ron is much more of a purist about nonintervention and that's fine, but in many ways Ron's foreign policy can exist only in an academic sense." I'm not necessarily interested in divining divisions between you and your son here, but what of that kind of notion that there is a purist libertarian ideal about nonaggression and nonintervention, but that in both political practice and in geopolitical reality, it couldn't actually work that way?

Ron Paul: Well, the only way you can find out is try it. It's true that pure nonaggression has never existed. Of course, there were experiments with pure communism, too, and that didn't do so well. But no, I don't think you have purities; no perfection. I think we have to try to understand these views and the philosophy. If we come to the conclusion that we definitely think it's better for humankind to pursue [nonintervention], we have to do our best to promote it. What is practical in one generation might be impractical for the next. You just don't know. Somebody might think it's impractical to be a noninterventionist right now. Well, what if we totally go broke and we've had such violation of our civil liberties that the people rebel and want a decent government over us? Maybe the most practical thing would be to move in the direction of what they call "impracticality" that we advocate. Who knows?

I think false expectations are bad; I think you have to be realistic. But I do believe you have to know what you believe in, because our opposition is interventionists. They intervene in the economy, they intervene in personal lives, and they intervene overseas. Republicans and Democrats, they endlessly argue about degrees. Should we bomb this week or next week? Should we use cruise missiles? Which company should we buy our helicopters from? It's all details of intervention. The argument has to be whether intervention is bad or good, and then you have to strive for the nonintervention. Because I think that is the only chance we have to work for a truly peaceful and prosperous world.