this is a moment that counts, on an important, time-sensitive issue, so here goes:
• The Obama Administration, along with some of the usual US allies—the UK, France, Germany—and such non-allied parties as Russia and China, has taken steps with the potential of peacefully ending Iran’s 35-year estrangement from most of the rest of the world. That would be of enormous benefit and significance to Iran, the US, and nearly everyone else concerned.

Obviously potential is not a guarantee, and a year from now everyone could look back on this as a time of deluded hope. But today’s potential is far greater than most “savvy” experts expected a year ago. As I argued last month, the US may be in a position right now with Iran analogous to the one with China in the early stages of the Nixon-Mao rapprochement. Nothing is guaranteed, but the benefits of normalized relations would be so great that they must be given every chance to succeed.

 • Often there is cleavage within the executive branch—State, Defense, the White House—on the merits of a military commitment or a potential deal. Not this time.

Very often there is similar disagreement among Western powers, and most of the time the Russians and Chinese find themselves on the opposite side of strategic calculations from the US Again, not now. All involved view the benefits of reengaging Iran to be so great, and the consequence of a drift toward war so dire, that they want to make sure that no artificial barriers to a deal get in the way. (On the dire consequences of a drift toward war: Nearly 10 years ago, The Atlantic ran a war game concluding that an air strike designed to take out Iran’s nuclear potential would be the height of strategic folly for the attacking party, whether Israel or the United States. Nothing that has happened since then makes it a more plausible option.)

• Two countries the US cares about are known to oppose this deal: Saudi Arabia, and Israel. The Saudis, because a stronger, oil-exporting, Shiite Iran probably means a less influential Sunni kingdom. The Israelis, because the Netanyahu government has launched disinformation campaign against Iran, with whom any deal or compromise is by definition doomed.

I believe that Netanyahu is wrong, but it’s his country, and he is the elected leader. I don’t like the idea of him (or the Saudis) trying to derail what our elected leaders so strongly considers to be in the interests of the United States.

• That derailment is what seems to be underway in the Senate right now. Republicans led by Mitch McConnell are pushing for a sanctions bill that is universally recognized (except by its sponsors) as a poison-pill for the current negotiations. Fine; opposing the administration is the GOP’s default position. But a striking number of Democrats have joined them, for no evident reason other than AIPAC’s whole-hearted, priority-one support for the sanctions bill.

In the long run, these Democrats are not in a tenable position. Or not a good one. They are opposing what their president, his secretaries of state and defense, our normal major allies, and even the Russians and Chinese view as a step toward peace. And their stated reason for doing so—that new sanction threats will “help” the negotiations, even though every American, French, British, German, etc., and Iranian figure involved in the talks says the reverse—doesn’t pass the straight-face test.

Via the AP: “I think that the Iran sanctions bill is meant to strengthen the president, not in any way impede the ongoing negotiation which should and hopefully will be successful,” Sen. Richard Blumenthal, D-Conn., a co-sponsor of the legislation, said. Oh sure. You can imagine what a person as smart as Blumenthal—or Chuck Schumer, or Cory Booker, or Mark Warner, all supporting the sanctions—would do to similar assertions in normal circumstances.

James Fallows is a national correspondent for The Atlantic and has written for the magazine since the late 1970s. He has reported extensively from outside the United States and once worked as President Carter’s chief speechwriter. This article was first published by The Atlantic.