That terse and ominous statement from Secretary of State Rex Tillerson (that's the whole thing, by the way), issued after a provocative medium-range missile test from the Hermit Kingdom, shows just how tense things are between North Korea and the US right now. The issue of what to do about the world's most erratic nuclear power looms large over this week's meeting between President Donald Trump and Chinese president Xi Jinping in Florida, and is one of the most intractable foreign policy problems the US has to deal with. North Korea and America have never been friendly, but right now they seem closer than ever to outright war.

But according to Rodger Baker, a North Korea analyst at the military intelligence firm Stratfor, if there's another Korean war, it probably won't start with carefully staged strikes. "Rarely, I think, do people wait until everything is ready before they go to war," he told me. Baker walked me through the first day of what he says is a much more likely scenario—a very fucked-up scenario—that brings the US and North Korea into conflict.

In February, Trump vowed that North Korea won't develop a nuclear bomb capable of hitting the US, but as is often the case, the president left the details entirely to our imaginations. In a recent interview with the Financial Times, Trump said he would "solve" North Korea with or without China's cooperation, a similarly vague sentiment. Last week, Tillerson said that the last 20 years of policy toward North Korea were a failure . "The clock has now run out, and all options are on the table," a White House official told CNN on Tuesday .

The US, Baker told me, will "go into full frontline alert posture right away anyway, because it's going to have to anticipate a North Korean response, and it's going to scare the North Koreans away from that response by putting everything on full operational posture."

The scariest potentiality of all is one in which the US feels threatened before a launch even happens and uses an offshore launcher to lob a cruise missile, blowing up the North Korean launchpad and probably at least a few North Koreans. All of a sudden, there's been an attack on North Korean soil. That means a lot of things are going to happen at once.

This is how wars start, Baker told me: "Some series of things where in a moment of heightened tension one decision is made, or two decisions are made, that heighten into something greater."

Any of these possibilities could lead to a situation, according to Baker, in which the US would feel backed into a corner. "It needs to make a clear demonstration against continued North Korean rocket and missile tests," Baker said. In that case, the US could "deploy the Aegis missile [defense] system and shoot one down." In another possible scenario, "they could use a cruise missile to strike it on the ground."

Even a relatively innocent test launch could lead to a rocket breaking apart over Japan. Its guidance system could fail and careen toward South Korea, or it could look like it's being aimed at a US Navy base, which might merit a preemptive strike in the eyes of the US.

When North Korea tests a missile, it alarms the world for two reasons. First, it's a highly provocative advertisement of the country's military sophistication and that makes everyone nervous, even China and Russia . But the second thing to keep in mind is that these launches fling a whole lot of metal and explosives into the air near populated areas. North Korea is rushing to develop nuclear-armed ICBMs without the resources of a more developed country. "That heightened pace means you also have a lot of errors," said Baker.

On a good day, North Korea's air force, along with its medium-range missiles, may be able to strike any of the US airbases in South Korea. Osan Air Base, which is 40 miles south of Seoul, is a good target. Knocking out at least some US regional air power, according to Baker, gives the North Koreans a little bit of breathing room.

Frontline artillery, a.k.a. "shelling," a tactic Baker called "somewhat indiscriminate," is the most obvious first response. According to a report from Stratfor published last year , most of North Korea's artillery would only be able to hit targets near the border or maybe the Seoul suburbs. But a few of North Korea's biggest guns, including the tank-mounted Koksan 170-mm (see video above), along with its 240-mm and 300-mm rocket launchers, are capable of bombarding Seoul itself.

But North Korea's generals—whose heads would be spinning after hearing they've just been attacked—will be wondering if there are more attacks coming. North Korea is obviously prepared for a quick response to the start (actually the resumption) of war on the peninsula, and it has a short window to put the hurt on the US before it loses a lot of its capabilities. If cooler heads don't prevail very quickly at command and control in Pyongyang, this becomes a real war.

Doing nothing is not an option for North Korea, but the country could settle for what Baker calls "front posturing"—moving troops into position for war. A lot of North Koreans pointing guns at their counterparts across the border is the best-case scenario at this phase.

This is a moment when everyone could stand down, Baker told me. The US could send a clear message to North Korea: We felt provoked, we launched a countermeasure, but now everyone can just cool it, OK?

If longer-range cruise missiles are in working condition, North Korea might have a decent shot at hitting US bases in Japan, too. Attacking Okinawa wouldn't do much strategically, Baker told me, but if they blow up the US base in Yokosuka, near Tokyo, "they can disrupt the US ability to run their major supply chains out of Japan."

Step 5: China and Russia Show Up

This war won't likely stay strictly between the Koreas and the US. It's a crowded geopolitical neighborhood, after all.

If we're this far along, we've already assumed that China hasn't tried to stabilize North Korea preemptively, but let's not forget that when all is said and done, China has no interest in a unified Korea that would presumably be allied with the US. "The bare minimum is China has to put a couple of divisions actively on the North Korean border, up their air defense, and up their air capacity around the area," Baker said.

Russia, similarly, would make its presence felt, Baker explained. Russia has a border with North Korea, and it has military ships and planes humming around. "It would have to do everything it could at least to secure that border and the water around there," Baker said, adding that on day one, "even if [Russia's] not a direct participant in the conflict, it gets drawn in very quickly."

Step 6: The US Matches North Korea's Escalation

The US responds to each of North Korea's measures as they come and tries to preempt others. That means the military's attention is divided, according to Baker, between trying to knock out the artillery firing on the South and taking out as much of the "air defense network"—North Korea's anti-aircraft weapons—as it can. "That gives you the ability to have aircraft roaming around to look for every time a new missile rolls out of a tunnel," Baker told me. Since much of North Korea's weaponry doesn't show up in satellite photos, the US needs planes to fly around and find it. "Once it pops out of the cave, it reveals itself," he said.

It's a grim game of whack-a-mole, where the more moles you whack, the easier it becomes to whack moles. If the US is able to knock out North Korea's air defense, "You have a lot of destruction of their military capacity," Baker told me.

Step 7: North Korea Plays Dirty

From the North Korean standpoint, Baker said, the idea is to create "as much chaos as you can." That means you don't play by the rules—called the Geneva Protocol—that say you shouldn't put chemical warheads on missiles. "North Korea is the underdog," Baker said. "It has to use whatever tools it has, and chemical weapons—at bare minimum—interfere with the speed and capacity of the US and South Korean response."