Reading Peter Beinart, David Frum and Jeffrey Goldberg’s debate on the merits of the Iran deal, I was struck by something. Take a look at Frum’s list of gives and gets in the deal:

What did the Western world get from the nuclear deal just concluded with Iran?

According to deal proponents—and assuming Iran does not cheat—a delay of about eight months in Iran’s nuclear-breakout time, for a period of 10 years.

What did the Western world give?

1) It has rescued Iran from the extreme economic crisis into which it was pushed by the sanctions imposed in January 2012—sanctions opposed at the time by the Obama administration, lest anyone has forgotten.

2) It has relaxed the arms embargo on Iran. Iran will be able to buy conventional arms soon, ballistic-missile components later.

3) It has exempted Iranian groups and individuals from terrorist designations, freeing them to travel and do business around the world.

4) It has promised to protect the Iranian nuclear program from sabotage by outside parties—meaning, pretty obviously, Israel.

5) It has ended the regime’s isolation, conceding to the Iranian theocracy the legitimacy that the Iranian revolution has forfeited since 1979 by its consistent and repeated violations of the most elementary international norms—including, by the way, its current detention of four America hostages.

That seems one-sided.

Frum’s point is that items 1-5 provide substantial benefits to the Iranian regime, and that therefore, in his opinion, we should have been able to get more for them. That may or may not be true, and my bet is on “not.” It’s worth recalling that none of the other parties to the negotiation favored a more-aggressive approach to Iran. It’s also worth noting that the overwhelming response from people who actually do arms control for a living has been positive – meaning that what we got, assuming what we wanted was arms control, wasn’t nearly as meager as Frum asserts.

But I notice something different. Frum is valuing what our side got based on what it’s worth to us (and undervaluing it). But he’s valuing what our side gave based on what it’s worth to the Iranian regime. And that’s the wrong way to tally a ledger.

The right way is to look at each side independently. What did we gain versus what did we lose. What did they gain versus what did they lose. If you want your deal to hold, you hope that each side decides that their side of the ledger nets out positive. That’s what we call a win-win. And that’s what this deal looks like to me.

It is clear that the United States didn’t get everything we wanted – or everything we initially sought – out of the Iranians. It’s also clear that the Iranians allowed their own red lines to be crossed – they didn’t get everything they wanted either. There was, in other words, a negotiation. But the big picture – an arms control agreement and an end to sanctions and diplomatic isolation – remains what it always was and always was going to be, because that’s what would allow both sides to see a positive sum at the bottom of the ledger.

From my perspective, everything we “gave” to the Iranians was something that benefitted us not at all to retain, because the purpose of the sanctions and the isolation was to get a nuclear deal. Normal relations with Iran should be a positive goal as opposed to something we “gave” in order to prevent Iran from going nuclear.

(I would argue, by the way, that the same is true on the other side of the ledger: a nuclear program, rationally, benefits the Iranian regime very little. But I also recognize that there’s no reason to assume that Iranian ideologues are any more rational than American ideologues, and that Iran has sought to become a nuclear power for reasons of national prestige since the Shah’s time.)

And holding out for more should be tied to a real prospect of achieving more – in other words, real prospect that continued isolation would deliver an Iran that recognized Israel, cut its ties with Hezbollah, etc.

But not everybody does the math that way. A significant number of foreign policy opinionators ascribe real value to making the right enemies. Iran is a self-declared adversary of America’s founded on a revolutionary ideology of political Islam. It engages in international terrorism and hostage-taking. It refuses to recognize Israel. For a significant faction of the commentariat, the United States should stand opposed to a regime like that for deontological reasons. Even if it’s imprudent to go to war with them, we should maintain our posture of enmity. And this deal seriously compromises that posture.

I’m not a pollyanna about the deal. Much analogizing has been made between the deal with Iran and Nixon’s opening to China, but I think the analogy has serious limitations – because who is the Soviet Union? ISIS? I do consider ISIS a serious threat, as well as a nightmarishly horrible regime, because, should it succeed in becoming a functional state, it will exert a radicalizing and destabilizing influence throughout the Sunni world. But that means that it poses the biggest threat not to Iran, but to states like Turkey and Saudi Arabia – which are tacitly or even actively supporting it. And greater involvement by Shia Iran in the war against ISIS is hardly going to motivate those powers to shift to opposition.

Moreover, I am highly skeptical that Iran’s regime would desire, or benefit from, an explicit realignment towards the U.S. And I am equally skeptical that Iranian dissidents will see the domestic opening they hope for as a result of the deal. I believe the Iranian regime is rational and will focus on regime survival first and foremost, and I don’t see why they will feel greater need to placate the opposition after delivering improved economic conditions for the Iranian people. Certainly, China hasn’t felt that need.

So why do I support the Iran deal, strongly? Because, from my perspective, there is a negative value to enmity with Iran and a positive value to an improved working relationship – independent of whether the deal is the best deal possible. Because I ascribe a very positive value to a deal that the arms control community in general considers quite strong, and exceedingly skeptical of criticism from quarters opposed to arms control in general. Because I’m aware that the track record of opponents to major diplomatic agreements is relatively poor in general. And because I think a war with Iran would be a catastrophic folly.

That’s reason enough, no?