Washington ? The rapid collapse of Saddam Hussein’s government may have served as a reality check for the remaining states in President Bush’s “axis of evil,” Iran and North Korea.

North Korea now says multilateral talks about its nuclear program — which the United States wants — are not a bad idea after all. Iran’s former president, long allied with Islamic hardliners against the “Great Satan” America, is advocating a referendum on renewing ties with the United States.

Other countries, too, are feeling the heat.

Syria found itself Monday on the receiving end of stern warnings against allowing Iraqi leaders to slip across its borders. Secretary of State Colin Powell said Bashar Assad’s government must “understand its obligations in this new environment,” and British Foreign Minister Jack Straw was blunt as well: “It is very important for Syria to appreciate that there is a new reality now that the Saddam regime is gone.”

“Saddam’s fall and the American military operation’s great success has had a real sobering effect on the Middle East. It’s a wake-up call,” said Scott Lasensky, Mideast expert at the Council on Foreign Relations.

Specifically, Iran and Syria are watching to see whether Saddam’s government folded under the sheer force of Bush’s pre-emptive strike doctrine or through a confluence of factors, including some from within such as a history of aggression, a secret arsenal of weapons and a support of terrorist activity, Lasensky said.

“If it’s in fact a doctrine-driven war, that’s even more sobering for these regimes,” Lasensky said. “What the administration should do is talk more about the exceptional side of this war. Let the impression of Saddam’s defeat sit with these leaders.”

Powell indicated Monday that the United States just may do that. Holding up Syria as an example, he called on all nations in the region to “review their past practices and behavior” in light of the dramatic change under way in Iraq.

Iran’s former president, Hashemi Rafsanjani, suggested over the weekend that Iran either hold a referendum or seek a decision from the Expediency Council advisory panel on restoring ties to the United States.

Danielle Pletka, a Mideast expert at the American Enterprise Institute, said Assad and Iran’s supreme leader, Ayatollah Ali Khamenei, have simply realized the political dynamic in the region is shifting.

“Leaders that are smart enough to make a rational calculation about that, I think, have more likelihood of surviving into the future than those who will not face up to a different world,” she said. “The Middle East is replete with leaders who have not had the best interests of their people at heart. They should look at the Iraqi people and worry.”

Or, as in North Korea’s case, at the war’s outcome. According to South Korea’s chief security adviser, the North Korean government realized that with Iraq neutralized, there was no tactical advantage in continuing to resist global pressure for inspections of weapons facilities.

“This war on Iraq seems to have become a significant opportunity in deciding the landscape of international politics,” Ra Jong-il, the South Korean adviser, said.