I have probably written many times in the past that Republicans hit a new low, but as of this week you can toss all those. This Senate letter is the definite low of all time. I didn’t think these people could shock me, but this one genuinely was shocking in so many ways—not least the dishonor it brings on the United States Senate—that every other nutso thing they’ve done drops down one notch on the charts.

Treason, as the Daily News blared? I don’t know for sure about that. But I know to a certainty that if a group of Democratic senators had done this to a Republican president, Republicans and conservative pundits would be screaming the T-word and demanding the Justice Department investigate the senators.

Imagine if, say, 47 Democratic senators had written an “open letter” (a moral cop-out that permits the senators to say that it wasn’t “really” a communication to Ayatollah Khamenei) to Mikhail Gorbachev in 1986 assuring him any treaty Ronald Reagan signed with him could and quite possibly would be altered or abrogated by them. Or worse still—imagine that 47 Democratic senators had written an open letter to Saddam Hussein in the fall of 2002 reminding him that only Congress could declare war and that most of them would long outlast President Bush, while closing on the breathtakingly cloying note of being happy to have enriched Saddam’s “knowledge of the constitutional system.” There seems to me no doubt whatsoever that some Republican senators and members of Congress would have been baying for Logan Act prosecutions.

Much as part of me might savor it, I don’t think we ought to go there. A far better punishment for these disgraceful intriguers would be for the letter to backfire and increase the likelihood of a deal being struck. And it might well have that effect: If the mullahs genuinely want a deal, then surely a threat like this from the Senate would make them more anxious to pursue one while they can, and then hope that Hillary Clinton, who’s indicated she’d support a deal, becomes the next president and can make it stick.

Let’s hope that’s the effect—but let’s never forget the intent. These Republican senators, says Trita Parsi of the National Iranian American Council, an advocate for a deal, can’t block a settlement; “but they can get the Iranians to think that it’s impossible to trust the United States,” he says. Thus, “the intent of the letter was to show the United States to be untrustworthy.”

It’s pretty amazing that members of the United States Senate would want to do that to their own country—not just in the eyes of Iran, but in the eyes of the five other powers involved in the negotiations. Three are some of our closest allies (Britain, France, and Germany). The other two are the not inconsiderable nations of Russia and China. All five have had negotiators sitting at the table with us and the Iranians for a year and a half. Wonder what they think of this.

It’s a disgrace, but only another in a long history of Republican-conservative disgraces with respect to Iran. Indeed these go back to 1953, when Dwight Eisenhower green-lighted the coup that Harry Truman had blocked. And they extend up to 2003, and the now largely forgotten but suddenly rather timely story of the Bush administration’s rebuff of an Iranian diplomatic overture that could have made the history of the U.S.-Iran relationship a very different one from what it has been.

It was all widely reported then; this Washington Post article provides a good rundown. In sum, it was a point in time when the (Shia) Iranian republic had been cooperating with the United States in tracking down some (Sunni) al Qaeda men; through a Swiss intermediary, Iran passed a letter to the White House feeling the Bush administration out on broad-ranging negotiations—possibly curtailing its nuclear ambitions, cutting back on its support for (or maybe even disarming) Hezbollah, and most strikingly of all, indirectly recognizing Israel’s right to exist—all in exchange for the lifting of American sanctions.

The offer was real. Whether it had Khamenei’s blessing, no one in the West really knows. Still, some elements in the Bush administration wanted to pursue it. But guess who won? As that Post story reports it, “top Bush administration officials, convinced the Iranian government was on the verge of collapse, belittled the initiative.”

We can’t know what might have happened. “But we do know one thing,” Parsi says. “When diplomacy is rejected, as it was under Bush, when the official U.S. policy was for regime change in Tehran, you give the Iranians every incentive to do everything they can to prevent the United States from pursuing regime change.” That means spreading its talons across Iraq, and it chiefly means, of course, pushing ahead full-speed with its nuclear ambitions.

Here’s part of what that rejection of diplomacy has done for us. In 2005, Iran put an offer on the table to the Europeans calling for it to keep 3,000 centrifuges. But that was rejected, because the United States wasn’t willing to talk to Iran. So what did Iran do? While we were refusing to negotiate and rattling the saber, they were building centrifuges to beat the band.

So today, Parsi told me, Iran has about 22,000 centrifuges, of which 9,400 are operational. Any deal is going to let Iran end up with around 6,000 centrifuges. That’s twice the amount it was asking for in 2005, when we could have struck a deal at 3,000. But we weren’t talking to Iran then, because it’s weak to talk to terrorists and because the regime was on the verge of collapse anyway, see?

Our years of resistance to diplomacy, a product of neocon doctrine and pressure, has thus made the situation clearly and tangibly worse. The Obama administration, and the other five powers, are trying to stuff back into the tube the toothpaste that Dick Cheney and his confederates squeezed out. And for its attempt to repair the gaping wound the neocons and their friend Mr. Netanyahu inflicted on the world, the administration is now subject to this poisonous and quasi-treasonous attack that is designed to increase the likelihood of war with Iran (Senator Tom Cotton, the letter’s author, spoke openly at the recent CPAC conference in support of regime change).

I applaud the seven Republican senators who did not sign the letter, even if it is a little like applauding the members of the Manson family who didn’t actually kill anybody. And for those who did sign, eternal shame. The only silver lining is that the right’s track record on Iran suggests strongly that the result will be the opposite of that which they desire.