In October of 1938, in the heat of the crisis over German intervention in Czechoslovakia, Winston Churchill appealed to the United States to help thwart the Nazi war machine. ''Does anyone pretend that preparation for resistance to aggression is unleashing war?" he asked. ''I declare it to be the sole guarantee of peace." The Allies were not prepared to resist German aggression at that crucial moment. The result was a policy of appeasement -- the infamous Munich Agreement -- which abandoned Czechoslovakia into Nazi hands and set the stage for Hitler's blitzkrieg in Europe.

In the current standoff with Iran, the West is approaching what can fairly be described as another Munich moment. Last week Iranian President Mahmoud Ahmadinejad vowed that no resolution passed by the UN Security Council could make Iran give up its nuclear program. ''The Iranian nation," he said, ''won't give a damn about such useless resolutions." Here is an Islamo-fascist regime apparently determined to acquire nuclear weapons, destroy Israel, and extend its radical ideology.

What is the United Nations prepared to do? The Security Council is meeting to consider punitive action against the regime, but Russia and China oppose sanctions because of their extensive financial and strategic interests in Iran. The European Union negotiations involving Britain, France, Germany, and Iran -- all carrot and no stick -- have been a huge failure. UN Secretary-General Kofi Annan, meanwhile, remains a passive bystander.

What should the United States do to avoid another Munich? If the Security Council fails to confront the Iranian threat, America must form an international coalition to disarm the regime, enforcing a range of targeted political and economic sanctions. It must place the potential use of force squarely on the table.

As America's closest ally, and the only partner able to contribute extensively to military operations, Great Britain must forge a strategic alliance with Washington to check Iran's nuclear ambitions. President George W. Bush and British Prime Minister Tony Blair should hold crisis talks to discuss a range of options. Both the United States and UK should push for Israel's admission to NATO as a security guarantee against Iranian threats. Finally, the Pentagon and the UK Ministry of Defense should discuss a potential Anglo-American military operation, sending a clear warning signal to the mullahs in Tehran.

Blair has already hinted at military action to halt Iran's nuclear development. In addition, British defense chiefs reportedly held secret talks last month with officials from Downing Street and the Foreign Office to discuss the implications of military strikes against Iran's nuclear facilities

No one doubts that air raids against Iran would present serious political and military risks for both the United States and British governments. Bush and Blair have approval ratings at all-time lows. With growing disillusionment in the UK and the United States over the war in Iraq, a campaign against the largest power in the Middle East would face strong domestic opposition. For Blair, the issue could split his Cabinet and the ruling Labour Party and prompt a rebellion by left-wing backbenchers, who favor a policy of appeasement toward the mullahs.

Yet the British prime minister and his closest advisers are acutely aware of the strategic -- and moral -- threat posed by Iran. Through their experience with Security Council negotiations over Iraq, they also understand the limits of international diplomacy. They're likely to conclude that the risks to British national security of a nuclear-armed Iran outweigh the political drawbacks of military action.

When Britain and America faced a similar crisis -- a totalitarian menace and a feckless League of Nations -- they sought one another out. As Churchill implored his American audience: ''We need the swift gathering of forces to confront not only military but moral aggression; the resolute and sober acceptance of their duty by the English-speaking peoples and by all the nations, great and small, who wish to walk with them."

Britain will likely walk again with the United States if it is forced to confront Iran militarily.


Nile Gardiner is a fellow at the Heritage Foundation and a former aide to Margaret Thatcher. Joseph Loconte is a fellow at the Ethics and Public Policy Center and editor of ''The End of Illusions: Religious Leaders Confront Hitler's Gathering Storm."