Before his inauguration, Donald Trump tweeted about North Korea's claim that it was fast acquiring an intercontinental ballistic missile (ICBM) that could reach parts of the US. "It won't happen!" is what he said.

But unfortunately the president was extremely wrong.

On Tuesday, North Korean state TV announced the successful launch of a missile it's calling Hwasong-14. The country claimed the the missile reached an altitude of 1,731 miles and flew 580 miles before landing in the ocean between Korea and Japan. The TV announcement said North Korea was now "a full-fledged nuclear power that has been possessed of the most powerful inter-continental ballistic rocket capable of hitting any part of the world."

Trump responded by implicitly blaming China for its failure to isolate the North. "Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us—but we had to give it a try," he tweeted on Tuesday. UN ambassador Nikki Haley threatened military action on Wednesday. Thursday morning in Poland, Trump hinted at a "severe" response. But while the Trump administration may talk tough, it's hard to even imagine what a smart next move would look like.

To get a stronger sense of what Trump can plausibly do about Kim Jong-Un's missiles, I talked to Bruce Bennett, a senior defense analyst at the RAND Corporation who specializes in nuclear deterrence, among other things. With that in mind, I put together a list of possible US responses to North Korea's expanding nuclear reach, and asked him to weigh the pros and cons for me. His opinions on these topics painted a nice picture of Trump's very unappetizing platter of options.

VICE: Let's start with China. Trump seems frustrated that China keeps going easy on North Korea. What can he gain by pushing China harder?

Bruce Bennett: Last year, [President] Xi Jinping said if chaos were to occur in North Korea, he wasn't going to let it happen. If there was chaos or war, he was going to stop it, which says he's prepared to introduce ground forces into North Korea, since politically, he can't even stop North Korea from launching ballistic missiles, let alone stop chaos or war.

That's a pretty strong statement. There's been some media discussion of Chinese exercises to prepare to go into the North. So we have to step back and say China possibly could do more, but they haven't reached the threshold where they're ready to do that yet.

Sounds great if your name is Donald Trump. What about the drawbacks?

From a US perspective, it would be great. From a South Korean perspective, it would be absolutely unacceptable, because Article III of the South Korean Constitution says the entire peninsula is Korean, which means North Korea is part of their country as far as they're concerned. So if Chinese forces move into North Korea, that's a Chinese invasion of Korea, and South Korea would turn to the United States and say, OK, we've got this mutual defense treaty, and our country's been invaded by China. We need you to come and help us deal with this.

The new South Korean president, Moon Jae-In, seems like he's more apt to express that kind of North-South unity sentiment than his predecessor.

That's right. It's on the upswing, and so we face a complication there. From [a US perspective], having China go in and grab the WMD sites, the nuclear sites in the northern part of North Korea, that would be cool. It'd be great. But our South Korean allies are not going to look at it that way.

Another thing with pros and cons is the Terminal High Altitude Area Defense (THAAD) system that the US is putting into place. That might help the US shoot down missiles, but Koreans keep protesting it. Is that going to jeopardize Trump's relationship with Moon?

THAAD is operating. The radar is operating. You have two launchers with eight interceptor missiles each that are operating in South Korea. But the other four launchers that the US has now brought to Korea? [President Moon is] not going to allow those to be set up until an environmental impact report is done, which will be about a year from now, most people anticipate. So that gives him a year to keep his coalition together for his internal program before he starts fighting with elements of his coalition who aren't going to like THAAD [being] completely operational. So he's taking the action that's politically expedient given his internal focus.

When that year is over, is he going to kick THAAD out?

Well he's said—and his unification minister and his foreign minister have said—they're not going to kick THAAD out. They're committed to it, but they could change their minds as well if politics changed internally. So we don't know what the ultimate outcome is going to be, but thus far they've been pretty powerful in their statements, saying they're going to keep THAAD.

Another idea is to push for a peace treaty, maybe by moving or canceling the annual joint US-South Korean war games that North Korea hates so much. What do you think of that?

China has, in particular, been proposing this—that North Korea terminate missile launches, and the US and South Korea terminate our exercises. The problem with military forces is if you don't train, they really start to lose effectiveness. So this is pushed by China to make the alliance less effective, and eventually to have the American troops leave the peninsula. China would presumably like that to happen. What China didn't say is that simultaneously North Korea [must] stop it's offensive military training. So China's not saying, North Korea, you stop your offensive training, and US, you stop your defensive training. They're saying that the US and [South Korea] should stop its defensive training.

Watch: Missile test throwdown!

Is there some other action that might move things toward actual peace talks?

My preferred option is to tell North Korea: Look, if you want to negotiate, turn over five nuclear weapons to the International Atomic Energy Agency (IAEA). If you do it, you've got an advantage because the IAEA will look at those weapons, and if they really are miniaturized, and if they really would work, then the IAEA will announce that that's the case, and many parts of the world will recognize that you're a nuclear power, which is exactly what Kim Jong-Un wants. Meanwhile, we get rid of five weapons, and we also get intelligence on them, which we sorely need. So let's give the American people something for any of the negotiating we're going to do, where there's really an outcome.

That's a fascinating idea, but on the other hand, what if every time they've generated a working nuke they've detonated it, so they don't have any lying around?

It would be calling their bluff. And I think [it] would be really reassuring to a lot of people, if they basically refuse to do it. [Kim Jong-Un] has every reason to do it and get recognized. They may still, out of principle, refuse, so we don't know for sure that he would refuse because he doesn't have the capability. But we should say that! We should say, If he has the capabilities, he would do this, so obviously he doesn't have the capability.

Let's talk about a surgical strike against nuclear facilities. Is there any chance the US could make a move like that and not trigger all-out war?

Think about it from the North Korean perspective. We go in to take out one of their major nuclear facilities. If they do nothing, they're inviting a repeat against other of their nuclear facilities. So from a deterrence perspective, they need to respond in a way which causes considerable pain on our part, and makes us conclude that the cost we're bearing is not worth the benefit we're achieving. That's deterrence. So North Korea is going to be compelled to do that.

OK, last but not least on our menu of options: What about a larger military campaign aimed at regime change?

Military action aimed at regime change is certainly possible. The problem we face is, usually when North Korea has carried out a major provocation—a nuclear test, or major missile test—Kim Jong-Un and his father before him have disappeared [for anywhere] from days to weeks, with no public mention of where they are, and what they're doing. They clearly try to hid themselves.

And remember how effective we were in finding Saddam Hussein? Even when we owned the territory because our troops were in control, it was very difficult. So we could argue that we're prepared to do a surgical strike. There's some chance we could get lucky and find out where he is, but there's a much better chance that we won't.

Am I missing any options?

There is another option. We have to recognize that Kim Jong-Un does most of his provocations for internal political purposes as much as anything else. He's got to prove that he's really an empowered leader, for a guy who's pretty much a weakling in many ways—economically, international politics, and so forth. We need to be prepared to break open their system with internal political responses. Those could undermine the machine, could lead to civil war in North Korea, and China doesn't want that kind of thing. But if we don't put him in jeopardy, he's never going to think that he should just stop what he's doing.