As you might expect for any foreign-policy “dispute” between Maverick and Grahamnesty, the point of contention here is whether we should intervene aggressively or really aggressively. Graham wants the U.S. in ASAP to help save Baghdad, and since that means fighting a Sunni jihadist threat that Iran’s also busy fighting right now, it also means de facto coordination. If you’re going to coordinate tactically de facto, why not just suck it up and talk to them about formal coordination? The better the cooperation is, in theory the quicker the task at hand can be accomplished. McCain, meanwhile, thinks it’s insane to be working with a country that’s spent more than 10 years aggravating the sort of sectarian resentment in Iraq that helped make ISIS possible. The only solution, he thinks, is to reduce that tension, and step one in that process is reducing Iran’s footprint in the country. In other words, the U.S. should take a larger role in the fight against ISIS so that the Iranians can withdraw.

Basically, they’re arguing over whether the U.S. should be a global cop or a global Robocop,

But the South Carolina Republican said in order to blunt Iran’s rise in the region, the U.S. must take the uncomfortable step of working with Tehran.

“The Iranians can provide some assets to make sure Baghdad doesn’t fall. We need to coordinate with the Iranians,” Graham said on CNN. “To ignore Iran and not tell them,’Don’t take advantage of this situation,’ would be a mistake.”

CNN’s Dana Bash seemed to be in disbelief: “It’s sort of hard for me to believe that I’m hearing a Republican saying, sit down and talk with … Iran.”

Seems like a shrewder strategy to “blunt Iran’s rise in the region” would be to force them to fight a two-front war against ISIS in Syria and Iraq without western help, not to start bombing their enemies while sternly warning them not to capitalize once we’re gone. McCain’s retort:

“The reality is, U.S. and Iranian interests and goals do not align in Iraq, and greater Iranian intervention would only make the situation dramatically worse. It would inflame sectarian tensions, strengthen the Islamic State of Iraq and Syria (ISIS), drive more Sunnis into ISIS’s ranks, empower the most radical Shia militants, deepen the Iraqi government’s dependence on Iran, alienate U.S. allies and partners in the region, and set back the prospects of national reconciliation.

“For all of these reasons, and more, the United States should be seeking to minimize greater Iranian involvement in Iraq right now, not encouraging it. That means rapid, decisive U.S. action to degrade ISIS and halt their offensive in Iraq. And it means dramatically increasing U.S. military assistance and support to moderate opposition forces in Syria that are fighting both ISIS and the Assad regime. The longer we wait to act, the more our Iraqi partners grow dependent on the Iranian regime. That is neither in our interest nor consistent with the values for which we stand.”

The X factor is Iran’s nukes, needless to say. If we make a deal with them to defend Baghdad together, the odds that Obama ends up bombing their enrichment facilities when, not if, our nuclear “deal” with them falls apart drop even further. That’s one of the reasons why Kerry supports direct talks with Iran on Iraq, I assume. The more cooperative Iran is with us on this, the more cover Obama will have later to defend his decision not to attack their program. (“They’ve showed they can be responsible actors. Relations between us have improved, reducing the threat they pose.” Etc.) Either Graham’s blind to the way the White House will use Iran’s help politically or he perceives no reason why teaming up to save Iraq would or should give the U.S. second thoughts later about bombing Natanz or Fordow. Essentially, he’s prepared to bomb Iran’s enemies this week and bomb Iran itself next.

Another way to approach this is to ask which is the bigger threat to U.S. national security — Iranian nukes or ISIS building a terrorist Disneyland in the Sunni parts of what used to be Syria and Iraq. The best outcome for America from the standpoint of cold realpolitik is a long war of attrition between them that weakens both sides, but there’s no guarantee that that happens. In fact, there’s a chance we’ll end up with the worst of both worlds: If Iran can drive ISIS out of Syria and away from Baghdad and southern Iraq, maybe they’d tolerate leaving them alone with their own little caliphate in Anbar province. Iran’s never had a problem with Sunni fanatics harassing Sunni regimes or targeting U.S. interests with terror attacks, as Al Qaeda could tell you. On the other hand, maybe ISIS is now so committed to sectarian war, if only in the name of rallying Sunnis in the region to the cause of jihad, that they won’t reach an accommodation with Iran, which means a long war. The question for U.S. strategists is how to avoid the Iran/ISIS “accommodation” scenario while also not increasing either one’s power much in the process. Is there a way to do that?