Sens. Ted Cruz (R-Tex.) and Rand Paul (R-Ky.) have often been joined at the hip. Paul ranted about drone attacks on terrorists at cafes; Cruz joined in. Cruz opposed any immigration reform bill that could conceivably pass;  Paul said he was for immigration reform in theory but, to no one’s surprise, managed to find a reason to vote against it. Cruz led the government-shutdown effort, which  Paul opposed until he supported it. Both opposed U.S. action against Iran’s closest ally, Syria, which had used WMDs. Both offered the view — peculiar in light of subsequent events — that we had no interest in Syria. (Iran surely did, and a more analytical approach might have led them to be more concerned about bolstering the Shia crescent.) Both decried the NSA surveillance programs, falsely claiming that it infringed on the Fourth Amendment and adopting the view that we had more to fear from President Obama than from failing to connect the dots with the help of metadata.

Sen. Ted Cruz on the Senate floor. (Associated Press)

Now, for the first time, we see a dramatic departure for Ted Cruz from his ideological comrade — that is, unless Rand Paul decides once again to mimic the position of a probable rival in 2016.

Cruz has gone all in on Iran. His denunciation of the Iranian regime’s human rights atrocities are stirring. He vilifies the interim deal. He demands that Iran recognize the state of Israel(!). He writes:

Likewise, the mullahs in Tehran can now laugh all the way to the bank while they spend the time and money they have gained in Geneva pursuing nuclear capability. And all Americans have bought for $7 billion is the prospect of additional negotiations that might result in progress at some point down the road. But given the unfortunate results of these most recent negotiations, it is difficult to place much faith in such rosy scenarios — especially as the existential threat represented by a nuclear-armed Iran makes North Korea pale by comparison.

Those who do not learn from history, the saying goes, are doomed to repeat it. In this case, we cannot afford to let the Obama administration learn on the job. It is time to recognize the hard lessons of the last 20 years and apply them to this process.

Now, I have no reason to doubt Cruz’s sincerity, although he may want to rethink his lack of concern about Syria and his views on anti-terrorism programs. (There is a bit of a disconnect between ferocious opposition of Iran and its  sponsorship of terrorists but reluctance to employ techniques helpful in combating those surrogates.) Cruz is an ambitious man, if nothing else, and he has — quite rightly, I think — figured out that there is no advantage in a GOP primary (populated by many pro-Zionist Christian conservatives) in going wobbly on Iran. He’ll not be suggesting — as  Paul does — that containment might be a possibility. In this case his opposition to all things Obama-related meshes nicely with the most politically viable position (pro-Israel, anti-Iran) for a 2016 political contender.

And so there stands Rand Paul, alone at last. His embarrassing utterances — suggesting that containing Iran is no more problematic than deterring the Soviet Union or that China might be helpful in dealing with Iran — are noteworthy, even for him, in embracing a warped view of the world that is simultaneously to the left of Obama and to the right of Pat Buchannan. Now Paul, too, is an ambitious man, one who tried to cozy up to Israel and thereby Israel’s conservative supporters in the United States. But he has arrived at the inevitable clash of his ideology and his ambition, his worldview and reality. If one is pro-Israel in any sense of the word, one cannot be anything but irrevocably opposed to allowing Iran to keep its enrichment capabilities and illegal nuclear sites.

So what will Rand Paul do? Will his “containment” musing go down the memory hole, or will he be the sole pro-Obama voice in the GOP when it comes to our most dangerous security threat? Now, one might conclude that he is as unfit to govern as Obama is — and would not have approached Iran any differently. But going forward he’ll now have to choose whether he is his father’s son when it comes to Iran or a plausible voice on foreign policy.

If, like Cruz, Rand Paul makes a stand against an Iran with a nuclear-weapons capability, he’ll have to stare down his most rapid libertarian fans. Moreover, some of his previous positions will prove to be highly inconsistent with newfound appreciation for the Iranian menace. He may discover we actually have interests in Syria. He might ruminate about the size and capability of our navy and air force. He might even want to make sure we’re gathering all the information necessary in case Hezbollah or Hamas pick up some fissile material. Once you pull on the thread of isolationist folly, it tends to unravel.