This was the day that President Biden and his team had feared for more than three months, the day that relatively low-level attacks by Iranian proxy groups on American troops in the Middle East turned deadly and intensified the pressure on the president to respond in kind.
With three American service members killed and two dozen more injured by a drone in Jordan, Mr. Biden must decide how far he is willing to go in terms of retaliation at the risk of a wider war that he has sought to avoid ever since the Oct. 7 terrorist attack by Hamas touched off the current Middle East crisis.
Until now, the president had carefully calibrated his responses to the more than 150 attacks by Iranian-backed militias on American forces in the region since Oct. 7. He essentially ignored the majority that were successfully intercepted or did little to no damage while authorizing limited U.S. strikes focused mainly on buildings and infrastructure after attacks that were more brazen, most notably against the Houthis in Yemen who have targeted shipping in the Red Sea.
The first deaths of American troops under fire, however, will require a different level of response, American officials said, and the president’s advisers were in consensus about that as they consulted with him by secure videoconference on Sunday. What remained unclear was whether Mr. Biden would strike Iran itself, as his Republican critics urged him to do, despite his own determination to avoid a full-fledged war.
“The three American service members we lost were patriots in the highest sense,” Mr. Biden said in a written statement issued on Sunday morning. He added: “We will strive to be worthy of their honor and valor. We will carry on their commitment to fight terrorism. And have no doubt — we will hold all those responsible to account at a time and in a manner our choosing.”
Administration officials and intelligence agencies were trying to determine Sunday if the attack in Jordan represented a deliberate attempt by Iran to escalate the conflict or was meant to be the same kind of limited attack its proxies have been mounting but in this case happened to be more successful through happenstance.
American officials have said for months that they did not believe Iran wanted a direct war with the United States and on Sunday had not changed that assessment publicly. But at the same time, officials said, Iran has used its proxy forces to keep up the pressure on the United States and Israel as Israel continues to pound Hamas in Gaza.
One senior American official, who spoke on condition of anonymity to discuss sensitive information, said on Sunday that the United States did not believe that Iran was intending to start a wider war with the attack in Jordan. But he cautioned that analysts were still gathering and evaluating the information available to determine if Iran ordered a more aggressive attack or a militia group decided to do so on its own.
While a wider conflict could serve Iran’s purposes, American officials have long thought that Tehran understood that a direct war with the United States would be deeply damaging. The Jordan attack came at a time when some American officials had been exploring the idea that Iran might be on the verge of trying to rein in some of its proxy forces, a theory that may be dashed by Sunday’s attack.
Republicans wasted little time on Sunday blaming the deaths of the troops in Jordan on Mr. Biden, with one senator even calling the president a “coward” if he did not respond more aggressively.
“The entire world now watches for signs that the president is finally prepared to exercise American strength to compel Iran to change its behavior,” said Senator Mitch McConnell of Kentucky, the Republican leader. Senator Lindsey Graham, Republican of South Carolina, said flatly: “Hit Iran now. Hit them hard.”
Republicans argued that Mr. Biden had emboldened Iran by appeasing the mullahs of Tehran. They cited his efforts to negotiate a new agreement with Iran curbing its nuclear weapons program and a deal securing the release of five imprisoned Americans in exchange for helping Iran access $6 billion of its own oil money that had already been promised to Tehran for humanitarian purposes under a policy approved under former President Donald J. Trump. That money was frozen days after the Oct. 7 attack by Hamas, which is backed by Iran.
Republican critics also argued that Mr. Biden’s failure to take more devastating action in the past three months left Iran and its proxies confident that they could act with impunity.
“He left our troops as sitting ducks, and now three are dead and dozens wounded, sadly as I’ve predicted would happen for months,” said Senator Tom Cotton, Republican of Arkansas. “The only answer to these attacks must be devastating military retaliation against Iran’s terrorist forces, both in Iran and across the Middle East. Anything less will confirm Joe Biden as a coward unworthy of being commander in chief.”
As for Mr. Trump, now the front-runner for the Republican nomination to challenge Mr. Biden for his old job, he claimed on social media on Sunday that “this attack would NEVER have happened if I was president, not even a chance.” In fact, Iran and its proxies did attack American and allied interests during Mr. Trump’s presidency, and at one point Mr. Trump called off a retaliatory strike that he deemed excessive. He did later order a strike that killed a top Iranian general, but when Iran responded with missile strikes that injured but did not kill American troops, Mr. Trump ordered no further action.
Mr. Biden has ordered military strikes on several occasions in the past few months, including on Christmas Day. Just hours after a drone strike by Iranian-backed militants injured three American service members, one critically, Mr. Biden ordered airstrikes in Iraq in response. He also ordered the U.S. military to target a militia commander blamed for the attack; American forces carried out the order on Jan. 4 with a drone strike in Baghdad that killed the commander, Mushtaq Jawad Kazim al-Jawari.
Until Sunday, the only American military deaths in the region since Oct. 7 came not under fire but during an operation in the Arabian Sea to interdict Iranian weapons to the Houthis. Two Navy SEALs were declared dead last week after one fell overboard and the other dived in to try to save him.
Mr. Biden was informed about the attack in Jordan on Sunday morning in South Carolina, where he was spending the weekend campaigning before its Democratic primary. Defense Secretary Lloyd J. Austin III spoke with the president, along with Jake Sullivan, the national security adviser, and his deputy, Jon Finer.
Later in the day, Mr. Biden and Vice President Kamala Harris joined a secure virtual discussion with Mr. Austin, Mr. Sullivan, Mr. Finer and other advisers, including Secretary of State Antony J. Blinken; Gen. Charles Q. Brown, the chairman of the Joint Chiefs of Staff; and Avril D. Haines, the director of national intelligence.
The president addressed the matter later during a stop at Brookland Baptist Banquet Center in West Columbia, S.C.
“We had a tough day last night in the Middle East,” he told the crowd. “We lost three brave souls in an attack on one of our bases.” After a moment of silence, he added, “and we shall respond.”
Julian Barnes and Helene Cooper contributed reporting.