WASHINGTON — There was little doubt when President Donald Trump ordered a fatal strike last week on Iran's Gen. Qassem Soleimani that Tehran would feel compelled to retaliate. The question was how hard — and what would Trump do next?

By limiting its initial response to airstrikes on an Iraqi base used by U.S. forces, Iran appears to have sought to leave Trump an off-ramp: score settled, no need to escalate.

And Trump, in his highly anticipated response on Wednesday, seemed inclined to take it — even as he insisted it was Iran's leaders, not himself, who was blinking first.

“Iran appears to be standing down," Trump said at the White House, in a speech that suggested he didn't plan to respond militarily. Instead, he vowed to impose new economic sanctions, a relative slap on the wrist for a country already accustomed to being one of the most heavily sanctioned nations on the planet.

In the aftermath of Soleimani's killing, there were multiple signs that Iran had tailored its response to be arguably commensurate with the action Trump had taken. The Iranians hit a U.S. military target rather than American civilians, just like the U.S. drone strike had taken out an Iranian military asset. Soleimani, perhaps the most powerful military official in Iran, was the long-serving head of its elite Quds Force.

Iran's strike hit on Iraqi soil, just like the U.S. strike that took out Soleimani. In symbolic signs of tit-for-tat retribution, the missiles came at about the same time of the night that the U.S. had killed Soleimani. An adviser to Iran’s supreme leader even tweeted a photo of the Iranian flag, just as Trump had tweeted the American flag in his first comment on the Soleimani strike.

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Iran’s military carried out the strike itself, using ballistic missiles launched from Iranian territory and acknowledged on the record by Iran’s government. That was a sharp contrast from Tehran’s usual modus operandi of using allied proxy groups in other countries to attack its targets while allowing the Iranian government plausible deniability.

And most important, Iran avoided inflicting American deaths, which would almost surely trigger enough U.S. outrage that Trump would be compelled to respond even more forcefully.

Trump said neither Americans nor Iraqis present at the base had been killed despite the dozen-plus ballistic missiles lobbed from Iran. In fact, there was a growing sense that Iran had deliberately missed hitting sites head-on that would likely inflict serious U.S. casualties, so as to make its point without overly inflaming the situation.

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Indeed, in Iran’s first English-language comment on the strikes on Ain al-Asad air base, Foreign Minister Mohammed Javad Zarif said his nation did “not seek escalation or war,” but merely to “defend ourselves against any aggression.”

“Iran took & concluded proportionate measures in self-defense,” Zarif, Iran’s chief interlocutor with the West, wrote on Twitter.

Iran’s supreme leader, Ayatollah Ali Khamenei, was more ominous as he addressed the nation to chants of “Death to America” and “Death to Israel.” Describing the strikes as insufficient to avenge Soleimani’s death, Khamenei called them “just a slap in the face” and suggested Iran could act in other ways to drive the U.S. out of the region, although he stopped short of explicitly calling for further Iranian action.

Yet in the hours after several waves of missile strikes on al-Asad, there were more questions than answers about what had transpired and what might come next.

Despite Trump's insistence that Iran seemed to be "standing down," it was unclear whether the strikes constituted the totality of Iran’s response or would be followed by further action.

Avoiding U.S. casualties preserved a sliver of possibility for both sides to save face, by arguing to their own domestic populations that the initial grievance by the other side had been appropriately avenged. That could avert what appears to be an eye-for-an-eye cycle of escalation that has threatened a full-blown war between a major Mideast military power and the United States — and possibly its Sunni and Israeli allies in the region.

For Trump, it could also allow him to argue that Democrats’ frantic reactions to his strike on Soleimani, with lawmakers warning he might have dragged the U.S. into a new war, were misguided and ultimately incorrect. That could embolden Trump as he seeks re-election to assert that his foreign policy decision-making had been vindicated when it mattered most.

But it was deeply uncertain whether Trump’s pugnacious disposition and previous vows to punch back if Iran retaliated would allow him to look the other way as opposed to volleying back even harder. Although Trump indicated in his White House address that no further U.S. military strikes were in the works, that could change if the missile strikes are followed in the coming days by additional anti-U.S. actions by Iranian proxy groups eager to further avenge Soleimani's death.

In the days after ordering the strike to kill Soleimani, Trump had said any Iranian response would be met by the U.S. “quickly & fully” and “perhaps in a disproportionate manner.” But in the hours Tuesday after Iran’s strike on U.S. forces in Iraq, Trump’s tenor on Twitter was far rosier: “All is well!”

Yet there were signs that the precise pattern of escalation that military experts had warned about in the days since the Soleimani strike was playing out as predicted. This time, it was Iran threatening an even harsher response if the other side didn’t back down.

Iran’s Revolutionary Guards, the elite military unit where Soleimani was the driving force, said any further U.S. attacks would lead to “a more painful and crushing response” that could strike in any country from which the U.S. launched attacks. That was a clear warning to regional nations like the United Arab Emirates, Qatar and Kuwait that house U.S. troops.

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Other statements from Iranian officials threatened to attack Abu Dhabi, in the UAE, and Haifa in Israel if the U.S. responded to the strikes. It was the latest indication that regional allies of the U.S. that are also foes of Iran could find themselves in the crosshairs because of the spiraling conflict between Washington and Tehran.

But even if Trump, who campaigned on a pledge to extricate the U.S. from Mideast military conflicts, feels inclined to avoid a new war as his re-election approaches, there are political forces seeking to hold him to an unyielding stance on Iran.

Sen. Lindsey Graham, R-S.C., a frequent informal adviser to the president on national security, said the strikes clearly constituted “an act of war.”

“The president has all the authority he needs” to respond, Graham told Fox News late Tuesday.

Complicating prospects for an off-ramp are the lack of open channels of communication between the United States and Iran, which haven’t maintained diplomatic relations in almost half a century.

During the brokering and implementation of the Iran nuclear deal under the Obama administration, there were nascent, quiet communications between U.S. and Iranian officials. Even those limited channels have all but closed during the Trump administration, which pulled the U.S. out of the nuclear deal as it ramped up a “maximum pressure campaign” on Tehran.

The United States could turn to intermediary, partner countries that maintain relations with both the U.S. and Iran, such as Qatar and major European nations. But Qatar is unlikely to seek to be heavily involved given Iran’s threat to target anyone who assists the U.S. in its response. And the Europeans have long been incensed by Trump’s Iran policy and even more on edge since his strike on Soleimani, widely regarded as an assassination of a foreign country’s military leader.

The two countries could turn to Switzerland, which represents U.S. interests in Iran, or Pakistan, which handles Iranian interests in the United States, although neither would be particularly efficient ways for Washington and Tehran to communicate about de-escalating the situation.

Both countries have diplomats posted to the United Nations, but that too is a fresh sore point between the countries. Iran’s government has accused Secretary of State Mike Pompeo of blocking a visa for Zarif to come this week to address the U.N. Security Council in New York, in what Iran argues is a violation of U.S. obligations under the U.N. Headquarters Agreement.