The latest line taken by critics of the preliminary deal over Iran's nuclear program is that they would have cut a better, stronger deal than President Obama did. Israeli Prime Minister Benjamin Netanyahu is pushing that notion hard, arguing that even now, hitting Iran with tougher sanctions wouldn't drive them out of negotiations in frustration, but instead would force them to accept much harsher terms.

Naturally, Republicans are echoing the claim.

"Is there a better deal to be had?" U.S. Sen. Lindsey Graham said over the weekend. "I think so. What I would suggest is if you can't get there with this deal is to keep the interim deal in place, allow a new president in 2017, Democrat or Republican, to take a crack at the Iranian nuclear program."

"The best deal I think comes with a new president. Hillary Clinton would do better. I think everybody on our side except maybe Rand Paul could do better."

But here's the thing:

-- We know for a fact that Netanyahu, Graham and the rest could not have negotiated a better deal. We know that because to negotiate a deal, you have to actually talk with the other side and negotiate. And throughout this process, they have objected to the very notion of negotiation and done everything they could to make it fail.

When the current round of negotiations was announced in November 2013, along with an interim deal to freeze and roll back portions of the Iranian program, Netanyahu condemned it as a "historic mistake" and immediately began to try to undermine it. He expressed no interest whatsoever in seeing the talks succeed, in part because he does not believe that any deal can be verified.

If you don't believe that a negotiated deal can be verified, then you cannot support a deal, period. Your only solution is to take total control of the country.

Graham is no better. He too strongly opposed the 2013 interim deal negotiated by Obama, ironically the very same interim deal that he now proposes should be kept in place indefinitely until Obama is gone as president. The South Carolina Republican also made clear back then what his "negotiating style" would look like: "Once you get them to the table, you let them know what the final deal will look like and say ‘Take this, or else!'”

And of course, it's that "else" that Graham really wants.

As far back as 2010, Graham has been publicly advocating not just "a surgical strike on (Iran's) nuclear infrastructure," but a major war that destroys Iran's navy, air force and Revolutionary Guard. "I think we're to the point now that you have to really neuter the regime's ability to wage war against us and our allies. …," he said almost five years, warning that an Iranian bomb was imminent. [We must] destroy the ability of the regime to strike back."

In fact, as a sign of the seriousness with which the GOP took the 2013 discussions, here was the reaction of John Cornyn of Texas, the Senate's No. 2 Republican:

It's important to point out that Graham, Netanyahu and others might still prove correct. It is all too plausible that a final deal can't be reached, that hardliners in Iran will succeed in stopping it just as hardliners in this country are attempting to do, or that once a deal is in place, Iran proves unwilling to live by the agreement.

But if that happens, all of the options available to us today, including military action, would still be available to us then. In fact, if Iran is caught cheating, we and our allies would enjoy considerable international support for doing whatever is deemed necessary as a response.

The opposite is not true.  If we are the ones who walk away from a deal, or if we take military action against Iran without fully exploring every other option, any hope of a negotiated resolution would vanish. And that's just fine with certain folks. As U.S. Sen. Tom Cotton admitted during a January speech to the Heritage Foundation:

"Certain voices call for congressional restraint, urging Congress not to act now lest Iran walk away from the negotiating table, undermining the fabled yet always absent moderates in Iran. But the end of these negotiations isn't an unintended consequence of congressional action. It is very much an intended consequence. A feature, not a bug, so to speak."