In the hours before President Trump’s State of the Union address last night, we learned that the president’s expected nominee for ambassador to South Korea, Victor Cha, will not be nominated — apparently because he didn’t agree with White House attitudes that a limited military strike against North Korea would blunt the threat from its nuclear program. In his address to Congress, Trump didn’t include his usual threatening rhetoric, focusing instead on the brutality of the North Korean regime. But he also stated that “complacency and concessions only invite aggression and provocation.”

Here at the Monkey Cage, we’ve looked at the U.S.-North Korea standoff from many perspectives — some more optimistic, others less so. Here are four takeaways from these posts to make sense of where things stand:

1. No matter what Trump says, there are powerful constraints limiting — but not eliminating — the chance of conflict.

In early January, Michael Horowitz and I argued at the Monkey Cage that structural constraints rein in the odds of war on the Korean Peninsula. Although both of us have published research on how leaders can influence the outbreak and conduct of war, we noted that in the case of North Korea, factors that leaders cannot realistically change or avoid — such as geography and military capabilities — make the prospect of war so unappealing that leaders have incentives to try to deter the other side, rather than escalate.

Picking up this theme, Dan Reiter argued this month that the historical record shows preemptive wars are rare. Although the “powder keg” image is powerful, most dangerous crises — think nuclear-era standoffs like the Berlin crisis or the Cuban missile crisis — do not escalate to war. As Reiter explained, most of the time, “preemptive wars just aren’t that tempting.”

What about the risk of miscalculation? As Or Rabinowitz outlined last September, there are many paths to a miscalculation in the U.S.-North Korea standoff. But as Reiter noted, states — including North and South Korea — are also pretty good at preventing lower-level provocations from escalating to war through miscalculation.

Of course, the risk of war with North Korea is not zero, and Trump may yet be the driver of it. The news last night that Cha, long thought to be the Trump administration’s pick for ambassador to South Korea, would not be nominated partly because of  disagreement over limited strikes against North Korea, may suggest that those who are not prepared to strike are not welcome in the Trump administration.

Even more remarkable was Cha’s op-ed outlining his concerns. Some have suggested that this unusual move indicates how seriously the administration has been considering a strike. And as I wrote not long after Trump’s election, my research shows that advisers’ statements can send signals that affect how policies are perceived by others in the bureaucracy, by Congress and by the public. But, ultimately, decisions for war lie with the president.

People watch a TV screen showing images of President Trump, left, and North Korean leader Kim Jong Un at Seoul Railway Station in Seoul on Nov. 21. (Ahn Young-joon/AP)

2. If war does occur, casualties are likely to be high.

If war does come, Tanisha Fazal’s research on developments in military medicine shows it will be particularly costly in human terms.

As Fazal explained, advances in military medicine depend crucially on airlifting soldiers off the battlefield to trauma centers, to prevent wounds from being fatal. In a Korean war, the United States might at least temporarily lose control of the skies, undermining its ability to airlift the wounded and increasing the number of dead.

3. Even if there is no war, Trump’s rhetoric may have consequences for U.S. alliances in Asia.

In August, after Trump’s comments about how North Korea would face “fire and fury like the world has never seen,” Mira Rapp-Hooper explained how Trump’s threatening rhetoric damaged the U.S.-South Korean alliance — by undermining South Korea’s trust in the United States.

In her roundup after Trump’s Asia trip in November, Rapp-Hooper also noted that the president’s efforts at reassurance go only so far. Since then, renewed diplomacy and small signs of cooperation between North and South Korea — particularly over the upcoming Winter Olympics — suggest that South Korea may be taking matters into its own hands.

But the military alliance between the United States and South Korea continues on a day-to-day level, as Oriana Mastro and Arzan Tarapore wrote this month, after a research trip to Seoul. They found that military cooperation between the United States and South Korea is still robust, aided by long-standing institutions and routines.

At the political level, however, Mastro and Tarapore reported far less-stable coordination — which is where Trump’s threats come in. By threatening a war that South Korea understandably wants to avoid, Trump risks allowing North Korea to drive a wedge between the United States and its longtime South Korean ally.

4. The United States still has imperfect knowledge of what’s going on in North Korea.

Finally, what about what we know about North Korea itself? Alex Bolfrass recently explained that although intelligence estimates of nuclear programs have historically been quite good, states tend to underestimate — rather than exaggerate — a country’s nuclear progress. What’s more, the larger and more complex the program, the harder it is to get good information.

In the case of North Korea, the United States is confronting a state determined to develop an advanced nuclear missile capability. Malfrid Braut-Hegghammer detailed why North Korea succeeded in developing its nuclear program where countries such as Iraq and Libya failed. One reason is that Kim Jong Un consistently made nuclear weapons his top priority. Yes, the speed of North Korea’s success took the international community by surprise, but Braut-Hegghammer concludes that there were good reasons for this success.

What’s next for the U.S.-North Korea standoff?

To some extent, the current standoff looks much as it would have had Hillary Clinton won the 2016 presidential election. A determined North Korea has succeeded in its long-standing goal of developing an advanced nuclear capability. But North Korea still shares a border with China and faces a formidable foe in the United States. If war did break out, it would be particularly costly in human lives. These structural pressures constrain any U.S. or North Korean leader — and may indicate why preemptive wars or miscalculation spirals are historically rare.

That doesn’t mean Trump’s words have no long-term impact. The president’s threats have effects not only on North Korea but also on U.S. allies like South Korea. In fact, in the absence of war, Trump’s rhetoric may ultimately mean that the United States simply has less influence over what happens in North Korea than it otherwise would.