ASPEN, Colo. — Former National Security Advisor Jake Sullivan suggested at the Aspen Security Forum on Friday that the U.S. strikes on Iran had not been necessary and didn’t accomplish the fundamental goal of permanently stopping Iran’s nuclear program.

Asked whether he wished that President Joe Biden had carried through with plans to strike Iran before he left office, Sullivan argued that the situation at the time had been ripe for a diplomatic solution.

“During the transition, we handed off to the Trump administration. The situation in which Iran was at its weakest point since 1979,” Sullivan said. “Hezbollah had been functionally defeated. Assad had fallen. Its air defenses had been destroyed, and twice, Iran had tried to hit Israel with large salvos and missiles, and twice, with American help ordered by President Biden, Israel defeated those attacks. So Iran was weak and vulnerable.”

“In my view, a weak and vulnerable Iran was susceptible to a very good deal that would lock Iran’s program in a box for decades, not just set it back for a couple of years,” Sullivan continued.

He said that, after the strikes, a very similar deal remains necessary, “which is what I think President Trump will pursue, because the only way to permanently end Iran’s nuclear threat, I think, is through diplomacy.”

Sullivan’s perspective separates him from some Senate Democrats who spoke earlier in the day at Aspen, who described the strikes as successful even as they criticized the administration’s failure to coordinate with Congress and also emphasized that negotiations must follow.