President Trump’s decision to violate our nuclear agreement with Iran and our allies was not unexpected, despite the breathless, time-wasting chatter leading up to his formal announcement.

He always said that the treaty must go. He ran on that as a prime campaign promise and this week fulfilled it.

More instructive, more important as we move forward are the reactions of elected officials and the disparity in their reasoning.

Sen. Charles Schumer, D-N.Y., minority leader in the Senate, was opposed to the treaty in the first place. Unlike some of his colleagues who condemned the deal even before the details were negotiated, he studied it, consulted experts on all sides and concluded that we could do better.

Yet on Tuesday he was unwavering in his criticism of the president’s unilateral move because of the damage it will cause.

“There are no reports that Iran has violated the agreement,” he said. Far from making the region or the world more stable or peaceful, this will divide an allegiance that needs more than ever to stay united. “And you’re probably making it harder to come to a North Korea deal.”

Also noting the obvious point that violating the agreement harms our ability to monitor activities in Iran was his fellow New York Democrat, Sen. Kirsten Gillibrand, calling the decision “shortsighted and dangerous. … Rather than unraveling nuclear oversight, we should be focusing on adding additional levers to address Iran’s dangerous behavior in the region.”

Rep. Sean Patrick Maloney, D-Cold Spring, who had acknowledged that the deal was flawed, nonetheless could see that “If we scrap the deal, abandon our NATO allies, and the Iranians start racing towards a nuclear weapon, we could easily find ourselves in another ground war in the Middle East.”

Those hoping for negotiations toward a new deal are likely to be disappointed now that President Trump has surrounded himself with advisors who persuaded President George W. Bush to go to war with Iraq.

All of this was lost on our other representative in Congress, John Faso, R-Kinderhook, whose support for the president seemed to be based on the mistaken premise that the treaty would somehow transform Iran into a neutral nation akin to the Switzerland of the Middle East.

“Their destabilizing activities in the Middle East have resulted in brutal carnage in Syria,” Faso said, although how an agreement on nuclear arms was supposed to change that he did not specify. “ … they continue to call for the destruction of the state of Israel. Until Iran decides to abandon its malign activities, the U.S. has no choice but to restore economic sanctions and withdraw from this deal.”

It is not clear what Faso thought the agreement was about, perhaps because he is not clear on that himself. As he should know from this recent trip to Korea, the specter of the United States violating a treaty on such flimsy pretense is not good at any time but it is especially dangerous at a time when we are trying to get the dictator of North Korea, a man who also has been developing a nuclear weapons program, to trust us.