After U.S.-Led Strikes in Yemen, How Wide Will the Middle East War Get?

From the outbreak of the Israeli-Hamas war nearly 100 days ago, President Biden and his aides have struggled to keep the war contained, fearful that a regional escalation could quickly draw in American forces.

Now, with the American-led strike on nearly 30 sites in Yemen on Thursday and a smaller strike the next day, there is no longer a question of whether there will be a regional conflict. It has already begun. The biggest questions now are the conflict’s intensity and whether it can be contained.

This is exactly the outcome no one wanted, presumably including Iran.

“We’re not interested in a war with Yemen. We’re not interested in a conflict of any kind,” John F. Kirby, a White House spokesman, said on Friday. “In fact, everything the president has been doing has been trying to prevent any escalation of conflict, including the strikes last night.”

Mr. Biden’s decision to unleash airstrikes, after resisting calls to act against the Yemen-based Houthi militants whose repeated attacks on shipping in the Red Sea were beginning to take a toll on global commerce, is a clear shift in strategy. After issuing a series of warnings, officials said, Mr. Biden felt his hand was forced after a barrage of missile and drone attacks on Tuesday were directed at an American cargo ship and the Navy vessels around it.

“This is already a regional war, no longer limited to Gaza, but already spread to Lebanon, Iraq, Syria and Yemen,” said Hugh Lovatt, a Mideast expert for the European Council on Foreign Relations. Washington, he added, wanted to demonstrate that it was ready to deter Iranian provocations, so it conspicuously placed its aircraft carriers and fighters in position to respond quickly. But those same positions leave the United States more exposed.

Over the course of 12 weeks, attacks on Israeli, American and Western interests have come from Lebanon, Iraq and Syria, prompting modest, carefully targeted responses from American and Israeli forces. The United States also issued warnings to Iran, which the Americans say is acting as a loose coordinator.