North Korean leader Kim Jong-un brought in the New Year on Sunday by proclaiming that his nation has “reached the final stage in preparations to test launch” a KN-08 intercontinental ballistic missile (icbm).

In the past, the North has tested short- and medium-range missiles but never a long-range icbm, which could potentially reach the West Coast of the United States. Such a test would violate international law and, if successful, could pose a nuclear threat to America.

The following day, President-elect Donald Trump took to Twitter to address the North Korean statement:

https://twitter.com/realDonaldTrump/status/816057920223846400

It is unclear whether Mr. Trump was saying the test itself “won’t happen,” or if he meant that the North reaching the U.S. with a nuclear weapon won’t happen.

If he meant the first, the next few months could prove him wrong. Pyongyang has repeatedly defied Washington and the international community in its drive to develop nuclear and missile programs. It has conducted test after test in brash defiance of international law and United Nations resolutions. Preventing a future test would be difficult to accomplish without a preemptive military strike or a missile interception early in the test.

Jeffrey Lewis, director of the East Asia Nonproliferation Program told cnn on Tuesday, “North Korea will probably test the KN-08 this year, no matter what Trump tweets.”

If Mr. Trump’s tweet referred to a test, it could also be viewed as a red line that he might later be bound to, in a situation similar to U.S. President Barack Obama’s 2012 red line warning the Syrian government against using chemical weapons. “I think this could be something that comes back to haunt [Trump],” said James Acton, of the Nuclear Policy Program at Washington’s Carnegie Endowment for International Peace think tank. “This was a foolhardy tweet for Trump to send given the enormous challenges of constraining North Korea’s nuclear and missile programs.”

If the North perceives the statement as a red line that is later ignored, analysts say it could intensify Kim Jong-un’s push against the status quo. Frank Jannuzi, head of the Mansfield Foundation Asia dialogue forum, said in an interview with Reuters: “I worry … that it only emboldens the North, because they see it for what it is: empty talk. It lays down a red line. … We don’t seem prepared to back up.”

To understand the depth of the difficulties Mr. Trump’s administration will face, read “Can He Make America Great Again?”