We say that evil is dark. But this metaphor is imprecise. Evil is actually intensely bright, so painfully bright that people look away from it. Many even deny its existence.

Why? Because once people acknowledge evil’s existence, they know they have to confront it. And most people prefer not to confront evil.

That is what led to World War II. Many in the West denied the darkness of Nazism. They looked the other way when that evil could have been stopped and then appeased it as it became stronger.

We are reliving 1938. British Prime Minister Neville Chamberlain went to Munich to negotiate with Adolf Hitler. He left believing Hitler’s promises of peace in exchange for Germany being allowed to annex large parts of Czechoslovakia. Upon returning to England, Chamberlain announced, “Peace for our time.”

The American and European negotiations with Iran have so precisely mirrored 1938 that you have to wonder how anyone could not see it.

The Nazi regime’s great hatred was Jews. Iran’s great hatred is the Jewish state. The Nazis’ greatest aim was to exterminate the Jews of Europe. Iran’s greatest aim is to exterminate the Jewish state. Nazi Germany hated the West and its freedoms. The Islamic Republic of Iran hates the West and its freedoms. Germany sought to dominate Europe. Iran seeks to dominate the Middle East and the Muslim world.

And exactly as Britain and France appeased Nazi Germany, the same two countries along with the United States have chosen to appease Iran.

Today, people mock Chamberlain. But just change the names, and you realize that we are living through a repetition of Munich. Substitute the Islamic Republic of Iran for Nazi Germany, the Ayatollah Ali Khamenei for Hitler, Barack Obama and John Kerry for Chamberlain, Israel for Czechoslovakia and for Europe’s Jews, and the increasingly unsafe world of 2015 for the increasingly unsafe world of 1938.

In fact, there is considerably less defense for the Iran agreement — which awards Iran $150 billion in currently frozen assets and the right to keep its nuclear program — than there was for the Munich agreement. Prior to 1938, Hitler had not publicly proclaimed his aim to annihilate Europe’s Jews. Yet, Iran has been proclaiming its intention to annihilate the Jewish state for decades. There were no massive “Death to America” demonstrations in Germany as there regularly are in Iran. In 1938, Germany had not been responsible for terror around the world as Iran is now. Nor was Germany responsible for the death of more than a thousand Americans as Iran has been.

Iran has been responsible for more American deaths in the past quarter-century than any other group or country. Col. Richard Kemp, the former commander of British troops in Afghanistan, and Major Chris Driver-Williams of British special forces, summarized it this way: “Iranian military action, often working through proxies using terrorist tactics, has led to the deaths of well over a thousand American soldiers in Iraq and Afghanistan over the last decade and a half.”

The Neville Chamberlains of 2015 defend the agreement with Iran on two grounds: that the only alternative is war, and that this agreement has the capacity to bring Iran into “the community of nations.”

The first is a falsehood for three reasons.

First, the alternative to this agreement was continuing and tightening the sanctions that were weakening the Iranian regime and greatly diminishing its ability to fund terror groups around the world. Second, because the agreement so strengthens Iran, it makes war far more likely. When evil, expansionist regimes get richer, they don’t spend their wealth on building new hospitals. Third, we have been at war with Iran for decades — but only one side has been fighting.

And whoever believes that the agreement will bring Iran into “the community of nations” betrays a breathtaking ignorance about the Iranian regime.

The Iranian regime is composed of religious fanatics who are morally indistinguishable from ISIS, al-Qaida, Boko Haram and all the other mass-murdering Islamist movements.

The Iranian regime has executed more people than any country except China (and probably North Korea, for which data are unavailable).

The Iranian regime has killed more than 6,000 gays for being homosexual.

No woman in Iran is allowed to leave the country or even to work outside her home without the permission of her husband. As Zahra Eshraghi, a granddaughter of the founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, has testified: “As a woman, if I want to get a passport to leave the country, have surgery, even to breathe almost, I must have permission from my husband.”

The Iranian regime repeatedly calls for the extermination of Israel. No other country in the world is committed to annihilating another country.

Iran is the world’s greatest funder of terror organizations.

The late Argentine prosecutor Alberto Nisman indicted Iran for establishing terrorist networks throughout Latin America, including Argentina, Brazil, Paraguay, Uruguay, Chile and Colombia, among other countries.

Iran funds and directs the Lebanese terror organization Hezbollah, the most powerful military organization in Lebanon.

Iran is the major funder of Hamas.

Iran has been responsible for terror bombings in Kenya and Tanzania.

According to the 9/11 Commission Report, eight to 10 of the 9/11 hijackers passed through Iran, and an American judge ruled that Iran bears legal responsibility for providing “material support” to the 9/11 hijackers.

Members of Congress who vote to uphold this agreement will be viewed as Chamberlain is viewed. The Left likes to talk about being on “the right side” of history. Enabling Iran to keep its nuclear facilities while gaining access to hundreds of billions of dollars is to be on the wrong side of history.

Question: Would any member of Congress vote for this agreement if Iran were situated at the American border?

Very few people have a chance to do something about the greatest evil of their time. Members of the U.S. Congress have that chance. That should trump loyalty to Obama and his appeasement of the greatest evil of our time.

This column was originally posted on TownHall.com.