The options for a nonmilitary response are becoming clear. On Wednesday, the United States circulated to members of the United Nations Security Council a draft resolution that would require all countries to cut off the North’s oil and all refined petroleum products; it would also allow the Security Council to designate North Korean ships that could be boarded and inspected using “all necessary measures,” meaning whatever force was needed.

Ultimately, Secretary of State Rex W. Tillerson has said, the idea is to force North Korea to the negotiating table, but only after it begins to show a willingness to stop testing and gradually disarm.

But as several of Mr. Trump’s advisers have noted in recent days, United Nations resolutions and negotiation strategies are for the medium term. How to handle the launch is the immediate, urgent question. Here is a look at the president’s choices, and their downsides:

A Pre-emptive Strike

Mr. Trump told friends that he was proud of the moment in April when he ordered an airstrike on an air base where the Syrian government was believed to have launched chemical weapons attacks. The bombing unfolded during a visit to the United States by President Xi Jinping of China, giving Mr. Trump the chance to tell him about it during dinner and to send an unspoken message about what might happen in North Korea if it, like Syria, crossed a “red line.”

Technologically, it would not be difficult to destroy North Korea’s missiles. American warships off the Korean coast could easily hit the North Korean launch site, which is near the Sea of Japan. They might even provide warning to the North Koreans to evacuate the base.

But unlike the Syrians, the North Koreans know how to strike back — on the South Korean capital, Seoul, or American bases in Japan. Not long ago, President Moon Jae-in of South Korea said he had a veto on American attacks on North Korea, and promised “there will be no war” on the Korean Peninsula. (The Americans have a different view, saying that when it comes to defending American territory, no other country has veto rights.)