Foran: Trump has suggested that unpredictability can be advantageous in foreign policy since then our adversaries won’t know what we’re going to do. What do you think of that?

Jervis: It is true that there could be some cases where being unpredictable could be advantageous. It might create an incentive for countries to want to get out of his way because they may be afraid of what he is capable of. It’s possible that it could be a deterrent. I think the odds of this working, in the sense of getting Iran to give up missile tests, seem low, but it’s not impossible. They may decide to back off. There’s of course a slight chance that Mexico may be afraid of what Trump might do, and decide to pay for the wall, but I highly doubt it. Getting into a conflict with the U.S. would be very costly for other countries. We are the umpteen-pound gorilla in the room, and there’s enormous harm and good we can do. In most cases, if countries can stay on the right side of the United States, they will probably hope that they can do it.

But on the other hand, many countries have a strong sense of nationalism and will not want to give into the United States. Getting into a conflict with the U.S. could be damaging to a country, but it could be still be beneficial to a leader who decides to do it because it might allow them to be seen as heroic within their own country. Unpredictability and scaring people could also backfire for Trump if countries feel that they are going come into conflict with Trump no matter what.

When you look at the reports that Trump was combative with the Australian prime minister, well the prime minister might walk away from that and say, ‘Well, if he’s just going to be aggressive and belligerent from the outset of this relationship no matter what we do, then why should we try to do what he wants?’ Similarly, the Iranians could decide that even if they didn’t launch another missile test, Trump would just find another way to punish them. If punishment seems unavoidable, there’s no point in trying to appease.

Foran: What do you think is more risky: The potential that the Trump administration could damage relationships with countries that have historically been our adversaries, or countries that have historically been our allies?

Jervis: Trump has talked about the idea that our allies don’t carry their own weight, and that is absolutely true, they don’t. But alliances are still absolutely central to defending our interests. American power in the world is enormously enhanced by good relations with significant alliance partners, and the alliances underpin a lot of the world order that keeps us relatively safe and prosperous.

And you can’t disentangle our relationships with our allies from our relationships with our adversaries. If Trump, for example, pursues policies that most leaders around the world believe are imprudent with respect to a country like Iran, and that in turn alienates our allies, it could embolden our adversaries. If I’m an adversary of the United States and I’m confronted by America on its own, that is much less deterring than if I’m confronted by a strong alliance. For some countries, that dynamic might even create an incentive to provoke the United States. If our adversaries think they can provoke Trump into taking action that will alienate America’s allies, that could ultimately benefit them, especially if it ultimately breaks up our alliances.