Missile launches are not forbidden under the 2015 nuclear accord reached between Washington and Tehran, which is one of President Trump’s complaints about the agreement he abandoned last year. But a United Nations Security Council resolution, passed just as the agreement was reached, says that “Iran is called upon not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology.”

Secretary of State Mike Pompeo has demanded that Iran cease all missile launches and testing and give up its arsenal of the weapons. Iran says it is under no obligation to do so, and notes that because it has no interest in nuclear weapons, it is not violating the wording of the United Nations prohibition.

Last week in New York, Iran’s foreign minister, Mohammad Javad Zarif, said that if the United States wanted to discuss missile limitations, it should begin by not supplying Saudi Arabia, the United Arab Emirates and other Arab states with missiles that threaten Iran. The test on Wednesday seemed meant to drive home the point that Iran had no intention on giving up on its own missile fleet.

The Shahab-3 is hardly a new weapon — it has been in the Iranian arsenal for two decades. Based on a North Korean design, called the No-Dong, it can fly about 1,000 kilometers. Variants can range farther, capable of striking the edge of Europe.

But more important, Israel and a number of Western experts say a nuclear weapon can be fashioned to fit in the missile’s nose cone. The test launch may also be meant to demonstrate that American efforts to sabotage the Iranian missile program, chiefly with bad parts, are not impeding its development.