President Obama’s vow to seek support in Congress for his proposed deal with Iran reminds us of the Norway Debate. This is the argument that erupted in the Mother of Parliaments in May 1940, after the Nazis invaded Norway. When the debate began, the architect of the Munich appeasement, Neville Chamberlain, was still prime minister. By the time it was over, Chamberlain was out and Churchill had been handed up as the war premier.

It’s unlikely that things are going to be so cut and dried when Mr. Obama’s proposed framework goes before the Congress. Our legislature, after all, can’t cashier a president quite the way Parliament can a prime minister. Nor can it elect the next executive. But what is about to take place will be no ordinary debate, either. This is going to be a test of the constitutional balance of power over foreign policy. It would be hard to overstate what hangs in the balance.

For Mr. Obama proposes that Congress enter a contract with a regime in Iran that Congress knows has lied to us, that has failed to abide by past agreements, and that can be counted on to violate the agreement the President wants to sign (and that declares the destruction of Israel “non-negotiable”). The president dast not even vouch for Iran’s integrity. He merely challenges the Congress to come up with a better idea. That is rank burden-shifting.

Let Congress return the burden to the President. Let it challenge the president’s claim that a negotiated agreement “is our best option by far,” or what the New York Times calls “unquestionably the best approach.” Such talk reminds us of Geoffrey Dawson, who was editor of the London Times in the 1930s and the journalistic apostle of Britain’s appeasement of Hitler; Dawson called one Nazi peace offer “the best immediate hope.”

Like Munich, the pact Mr. Obama has just proposed was too much wanted. It’s a classic condition of appeasement. No wonder the Iranians are literally dancing in their streets. It’s a sentiment that is shared nowhere outside of Iran save for the Nobel Prize Committee, which is, one can hazard, preparing to give its medal in peace to Secretary Kerry and Foreign Minister Zarif. In America the proposed pact is being received with a decided glumness.

We have opposed the Iranian talks from the start, and what Mr. Obama proposes underscores our main point — that the parley itself is the appeasement. The very fact that these talks were taking place has aggrandized our adversary, cost us time, and — by betraying our closest (and only democratic) ally, Israel — courted “war with dishonor,” as Duff Cooper famously put it before resigning from the British government after Munich.

It’s unlikely that a Duff Cooper will emerge from the Obama administration. It will be up to Congress to choose the shape of things to come (which was the title of H.G. Wells’ 1933 novel predicting World War II). It wrote the sanctions that Mr. Obama proposes to dismantle. The Speaker has been making his own swing through the Middle East. He knows that it is Congress that was granted the power to regulate commerce with foreign nations. The President proposed. Now let Congress dispose.