Does the old cliche “the enemy of my enemy is my friend” apply to the ongoing conflict between the United States and the Islamic State? According to retired Army general and current CIA Director David Petraeus, teaming up with America’s enemies may be the best way to crush ISIS once and for all–even if it means cooperating with al Qaeda.

Petraeus became a general in 2007 and was appointed the commander of all Iraq and Afghanistan forces in 2010. During that time, Petraeus convinced Sunni militias to stop fighting against Americans and start fighting with them against hostile terrorist cells. The tactic didn’t stomp out radical Islamism entirely (exhibit A: ISIS), but it did all but destroy al Qaeda.

Now, Petraeus is suggesting that the United States team up with al Nusra, an al Qaeda spinoff organization that is a sworn enemy to ISIS, in order to stop the spread of ISIS influence throughout the Middle East.

Here is Petraeus’ statement explaining his plan:

We should under no circumstances try to use or coopt Nusra, an Al Qaeda affiliate in Syria, as an organization against ISIL. But some individual fighters, and perhaps some elements, within Nusra today have undoubtedly joined for opportunistic rather than ideological reasons: they saw Nusra as a strong horse, and they haven’t seen a credible alternative, as the moderate opposition has yet to be adequately resourced.

The question, therefore, is whether it might be possible at some point to peel off so-called ‘reconcilables’ who would be willing to renounce Nusra and align with the moderate opposition (supported by the U.S. and the coalition) to fight against Nusra, ISIL, and Assad. Doing so would require both the rise of much stronger, moderate opposition groups — backed, again, by the U.S. and the coalition seeking to defeat ISIL — and at the same time, intensified military pressure on all extremist groups.

There are a lot of obvious reasons why this ploy would never be accepted by the American public or military. Al Qaeda was the organization that orchestrated the 9/11 terrorist attacks, and many Americans lost their lives in the ensuing war on terror. It’s likely that al Nusra agents would also refuse to cooperate with the United States given the bad blood and anti-American sentiment on their side.

Christopher Harmer of the Institute of the Study of War told the Daily Beast that Petraeus’ plan is a testament to how difficult the war with ISIS has become. “This is an acknowledgment that U.S. stated goal to degrade and destroy ISIS is not working. If it were, we would not be talking to these not quite foreign terrorist groups,” Harmer said. “Strategically, it is desperate.”

The reason al Qaeda exists at all is because the United States nurtured and worked with the fundamentalist group to stop the Russian invasion of Afghanistan. To borrow yet another cliche, we can’t help but wonder whether history is repeating itself.