President Trump’s decisions to order and then suddenly abort a military strike against Iran set off a debate across the region on Friday over whether his stop at the brink amounted to his gravest threat yet or a sign of capitulation.

Iranians, locked in an escalating standoff with Mr. Trump over the previous six weeks, quickly sought to portray the aborted strike as evidence that he had blinked first, proving what they called his reluctance to fight and eagerness to compromise.

Iranian foes in neighboring countries like Saudi Arabia, the United Arab Emirates and Israel, on the other hand, argued that Mr. Trump’s willingness to come so close to military action — with warplanes in the air, ships in position, and missiles minutes from launching — instead meant that Iran should expect an even more serious retaliation if it sought to lash out again at the United States or its close allies.

And the ambiguity itself, some argued, may now pose its own danger: Hard-liners in Iran could become emboldened to further test Mr. Trump. But at the same time he has raised the expectations among some of his closest allies that he will let the missiles fly the next time.