Demonstrating the capacity to surprise, North Korea’s Kim Jong-un acted like a modern statesman when he ventured into the Republic of Korea for his summit with South Korean President Moon Jae-in. That doesn’t mean Kim and his heavily armed nation are not potentially dangerous. But after watching Kim in action, as Margaret Thatcher said of Mikhail Gorbachev, “we can do business together.”

Reasons for caution are many. After all, Kim’s father had summits with two successive South Korean presidents, but by earlier this year people were talking about the possibility of nuclear war between the U.S. and North Korea. However, despite the danger of excessive expectations, the diplomatic option first advanced by Kim has shifted the peninsula away from military conflict, at least in the short-term.

Which is a major benefit. As I point out in a new study for Cato, war simply is not an option. It wouldn’t be “over there,” as Sen. Lindsey Graham (R‑SC) infamously assured us. Americans would be directly involved, even if the North was not capable of striking the U.S. homeland. In any case, if war resulted, the likely death and destruction on the peninsula, with South Korea a major part of the battlefield, and likely beyond, including Japan, would be far too great to justify the risk.

As a result, President Donald Trump should have modest expectations when meeting Kim. The president’s goal should be to set in motion negotiations and actions that will reduce the likelihood of conflict and hopefully, ultimately, lead to full denuclearization.

One of the most important offers he could make to advance the negotiations is to bring home U.S. troops from the peninsula. Although the American presence is viewed as near sacrosanct by many analysts, Defense Secretary Jim Mattis said that withdrawal is one “of the issues we’ll be discuss in in the negotiations with our allies first and, of course, with North Korea.” He rejected having “preconditions or presumptions about how it’s going to go.” In fact, the ROK’s rapid economic growth and democratic evolution long ago made Washington’s conventional security guarantee obsolete.

But even something short of denuclearization could promote stability and peace on the peninsula and throughout the region. Which would be an accomplishment President Trump could rightly celebrate.