It was “a very significant effort to re-establish deterrence, which obviously had not been shored up by the relatively insignificant responses up until now,” Petraeus told Foreign Policy magazine.

James Phillips, a senior research fellow at the Heritage Foundation, said it was important for the Trump administration to enforce its red lines after having shied from responding for so long.

But it is hard to establish credible deterrence against a regime like Iran, where Soleimani’s Revolutionary Guards were “willing to sacrifice Iran’s national interests in order to advance the regime’s more narrow revolutionary interests,” Phillips said.

“I think, unfortunately, also Tehran may have interpreted the Trump administration’s previous restraint as weakness.”