Foreign policy analyst Walter Russell Mead warned on Wednesday that the next administration will likely need to confront a nuclear armed Iran, or take steps to prevent Iran from obtaining a nuclear weapon. But he said he doesn’t think either presidential candidate is fully prepared for that scenario.

“My guess is that the next president will likely face a nuclear Iran — or face the alternative of war with Iran or accepting a nuclear Iran,” Mead said in remarks at the American Enterprise Institute. “I don’t think either candidate really knows what they would do under those circumstances, but I think that is something they are very likely to face.”

Mead described Iran as having the most success in altering the world to its goals despite being the least capable of the U.S.’ three major global adversaries (Russia, China and Iran): “The runt of the litter is running the table.”

He blamed the situation on “American weakness and unwillingness to face reality in the eye,” and called the blockade of Red Sea trade by the Iran-backed Houthis an “extraordinary retreat.”

Mead said that diplomacy with Iran is a fallacy, given that the regime has made clear it has no intention of becoming a friend of the United States, and instead benefits from hostility toward the U.S.

But he said the U.S. can’t allow Iran to gain a stranglehold on the region, particularly on the flows of oil.

“We seem to be on a collision course in which, if we don’t take adequate steps to defend a vital interest, we’ll have to live with the very, very serious consequence of a bunch of people who hate us in Tehran being able to hold the world economy to ransom, more or less at will,” Mead said.

Mead offered praise for Saudi Arabia, saying that it has “done almost everything we’ve ever asked.” As such, he continued, the U.S. should be bringing its allies including Saudi Arabia, Israel, the United Arab Emirates together to deal with the Iranian threat and giving them what they ask for to protect themselves.

“I would think we should be encouraging our regional allies to take the lead in what is an existential issue for their own future, and letting it be known, publicly and privately, we will back you to the hilt,” Mead said.

Mead’s presentation, more broadly, warned about the decline of the post-Cold War Pax Americana age. He said that “everything in history tells us this looks like a pre-war era,” and the U.S. must take serious steps to prepare.

Reflecting on research for his 2022 book, The Arc of a Covenant: The United States, Israel, and the Fate of the Jewish People, Mead said he found that antisemitism ebbs and flows over the course of U.S. history, and that it tends to surge “when the American system comes under stress and people begin to doubt that things like the American melting pot, the American Dream are real and work.”

He said the U.S. currently finds itself in another such period, with the some arguing that the “idea that we could be a multiethnic, multiracial society [is] really just the mask that white supremacy uses to enforce a certain hierarchy,” and others promoting the Great Replacement Theory, “that real America is being destroyed by fake America.”

“As these ideas come out, we see the old demons are coming out again,” Mead continued. “The sun goes down, and strange things come out of the shadows.”