Why It Matters That Colin Powell and Debbie Wasserman Schultz Support the Iran Agreement.

A Republican former secretary of state and a Democratic "Jewish mother" may have just given us the strongest case yet for the nuclear agreement with Iran.

The first is a pillar of the "realist" camp in the American national security establishment. The second is a rising star in the Democratic Party from a heavily Jewish district in South Florida. Together, they represent key constituencies whose support for the historic accord is critical to isolating right-wing opponents and preventing last-minute sabotage attempts.

Together, they also lay out a compelling narrative of why the agreement is so important to American national security.

Colin Powell begins his short narrative with a clarifying analogy that -- surprisingly -- hasn't been used before. He told Chuck Todd on NBC's Meet the Press on Sunday:

Here's why I think it's a good deal. One of the great concerns that the opposition has, that we're leaving open a lane for the Iranians to go back to creating a nuclear weapon in ten or 15 years. They're forgetting the reality that they have been on a superhighway for the last ten years to create a nuclear weapon or a nuclear weapons program, with no speed limit.

And in the last ten years, they have gone from 136 centrifuges up to something like 19,000 centrifuges. This agreement will bring them down to 5,000 centrifuges. All of these will be under IAEA supervision. And I think this is a good outcome.

The other thing I've noticed is that they had a stockpile of something in the neighborhood of 12,000 kilograms of uranium. This deal will bring it down to 300 kilograms.

It's a remarkable reduction. I'm amazed that they would do this. But they have done it. And with respect to the plutonium effort, the plutonium reactor at Arak, which is now starting to operate, it's going to be shut down, except for minor parts of it, and concrete will be poured into the reactor core vessel.

So, these are remarkable changes. We have stopped this highway race that they were going down.

Powell cuts to the core of the issue. The Iran Agreement shrinks Iran's program, freezes it and wraps it in an inspection regime stronger than any ever negotiated.

The opposition really doesn't have a rebuttal to this. That is why they have spun up minor issues to absurd heights, while ignoring the central accomplishments of this painstakingly-negotiated accord.

Representative Debbie Wasserman Schultz from the Miami area, the chair of the Democratic National Committee, was under intense pressure from groups aligned with Israeli Prime Minister Benjamin Netanyahu to oppose the agreement. She went through a "gut-wrenching" process, she says, before deciding this was the best way "to prevent Iran from achieving their nuclear weapon goals."

But to get to that point, she first had to examine carefully all the alternatives. None were real, she told CNN's Jake Tapper.

The first is the myth of a "better deal." This is the idea that all we have to do is reject this agreement, impose new, unilateral sanctions on any nation that traded with Iran and we could then force Iran to scrap its entire nuclear complex.

Not true, Wasserman Schultz, found out.

In thoroughly reviewing opponents' claims that we could using our banking system, for example, to wrestle our allies and Iran back to the negotiating table for a so-called better deal, no one presented me with any evidence to show me that that was possible.

And in talking to our allies' ambassadors, in talking to nuclear experts, in talking to our intelligence officials in top-secret briefings, in talking to [Treasury] Secretary Lew, it was very clear that global economic chaos would be caused if you had even attempted that...

And if we walk away from the deal, then what results is, they have additional resources. They still have the ability to ramp up and move towards their nuclear weapons goals. And we have none of the monitoring, none of the accountability, none of the inspections.

That is about as clear a rebuttal of the fantasy alternatives as one can give. She did it better than I did in a recent oped for the Los Angeles Times.

But Debbie isn't done. She then takes dead aim at the latest tempest in a teapot: the claim that Iran will "self-inspect."

Tapper asks her, "A few weeks ago, the Associated Press revealed that they had seen a document that would suggest that Iran, when it came to the military installation at Parchin, Iran would get to self-inspect."

Nonsense, she says, with conviction and evidence.

That story came out the day before I had an entire morning's worth of briefings, top-secret briefings in the Situation Room. I brought that story into the Situation Room...and I said, "If this is true, I am a no. I want you to clearly understand that. You need to address this concern."

And I was given probably the most thorough review that almost any member had access to as far as what the actual process is for Iran to reveal their previous military dimensions at Parchin. And I can say in no uncertain terms, without revealing the details, that they cannot self-inspect.

Absolutely cannot, and that the IAEA -- and, in fact, the head of the IAEA came out immediately -- and they hardly ever comment, Jake, but the head of the IAEA said that that was absolutely not the case. It's an excruciatingly detailed process that they will have to go through to certify.

Nuclear experts agree. But having Debbie Wasserman Shultz say it, after over a dozen briefings and access to our best intelligence, is a powerful rebuttal. Particularly when she adds her pledge that she would never support any agreement that weakened Israel's security.

"I'm the first Jewish woman to represent Florida in Congress. I'm a Jewish mother," she said.

There's nothing more important to me, as a Jew, to ensure that Israel's existence is there throughout our generations. And I'm confident that the process I have gone through to reach this decision is one that will ensure that Israel will be there forever. It's the homeland of my people.

The Iran Agreement does not resolve all the issues with that nation that justifiably trouble Americans and Israelis. But, as Powell points out, it resolves the most important. "This deal specifically had to do with the thing that was most concerning to the world, most dangerous to the world," he says, "And that was their nuclear program, which could produce a weapon in a very short period of time."

That has been thrown into a detour. It isn't going to happen. And in ten or 15 years, we don't know what the future will hold. But it's not clear that in ten or 15 years from now, they will want to start it up again, or the material that has been under IAEA supervision for the ten or 15-year period will be available or suitable for such an increase. And so that's pretty good.

Powell and Wasserman Schultz did more that pretty good on the Sunday talk shows. They nailed it.