Well, we'll see.

Iran and six major world powers, including the United States, have announced a tentative  and potentially historic agreement in which Iran will allow intensive, ongoing inspections of its entire nuclear program, cease some aspects of that program and surrender a stockpile of highly enriched uranium. In return, the tough international sanctions that drove Iran to negotiate will be relaxed as it carries out its obligations.

Skepticism is still justified, even mandatory. We're still a long way from a final deal. And for some in Congress, of course, this deal won't be deemed acceptable because they believe that no deal would be acceptable. The only resolution that they are willing would be regime change in Iran, with the current Islamic dictatorship replaced by a government that is friendly to the United States.

Certainly, that would be nice. Many things would be nice. The problem is that advocates of that coures have yet to explain how such a lofty goal might be achieved or how Iran's nuclear program could be stopped while that long-off goal of regime change is pursued.

Let's also put this into context: Back during the 2008 campaign, then-Sen. Barack Obama took considerable criticism for saying that if elected president, he would agree to negotiate with his Iranian counterparts. Later, as his administration attempted to work with Russia and China to cooperate on imposing tough sanctions against Iran, critics dismissed such cooperation as impossible, arguing that those two countries would never be willing to help us. Once those sanctions were in place, with Russia and China's full cooperation, critics insisted that they would never succeed in driving Iran to negotiate.

Once negotiations began, they insisted that Iran would cheat on its obligations under the interim agreement to surrender nuclear material, cease operations and allow inspections. Once again they were wrong: Iran did not cheat. And even as Iran continued to meet its obligations and continued to negotiate in apparent good faith, critics claimed that in the end, Iran's leadership would never accept the highly intrusive, longterm inspections and other steps that were outlined today.

As Obama noted in announcing the deal, it will be the United States, not Iran, whom the rest of the world will blame if Congress decides to undercut it. In the wake of such a tragic mistake, it would be all but impossible for the United States to rally the rest of the world to reimpose sanctions. Nor would they join us in taking military action. We, not Iran, would be the rogue nation. And those who made a negotiated outcome impossible would become responsible for what would come next, which would likely include the threat of a major war.

It would be deeply, profoundly irresponsible to allow this deal to be destroyed by partisan interests and an instinct to deny Obama any accomplishment, without at least taking an open-minded look at what the deal contains and what our remaining alternatives might be.  Yet some in Congress appear eager to do exactly that. It was remarkable, for example, to see 47 GOP senators write an open letter to Iranian leaders last month, warning them that the United States could not be trusted to honor any deal they might reach, before they even knew what such a deal might be.

And it was downright chilling to hear Sen. John McCain on the floor of the U.S. Senate last week, implying that Israel ought to destroy any chance of a negotiated settlement by acting on its repeated threats to launch a military attack against Iran:

"Here is my advice to the Israeli government, along with every other country being treated disdainfully by this crass administration: Repay contempt with contempt," McCain said. "The Israelis will need to chart their own path of resistance. On the Iranian nuclear deal, they may have to go rogue. Let's hope their warnings have not been mere bluffs. Israel survived its first 19 years without meaningful U.S. patronage. For now, all it has to do is get through the next 22, admittedly long, months."

There is something deeply disturbing, and disturbed, about such comments. I do not understand them or comprehend them, but I do know that it would be extremely dangerous to turn control of our nation's foreign policy over to such people. There has to be a better, saner course.