(CNN) -- The Pentagon's recent statement that Iran may have conducted air strikes against ISIS targets in Iraq's Diyala Province is tantamount to a U.S. tacit approval of Iran's growing military footprint in Iraq.

No military operation of such scale evades detection from U.S. radars. Even if not pre-approved or coordinated, Iran's air and ground operations against the murderous thugs of self-proclaimed caliph Abu Bakr al-Baghdadi make the Islamic Republic effectively a U.S. partner in the fight against America's greatest enemy: Islamist fundamentalism.

The U.S. strategy towards the Middle East since the Arab Spring has been defined by proactive disengagement and hesitance.

Haunted by the legacy of Iraq and Afghanistan, the American public has no stomach to get bogged down in lengthy ground-intense military operations -- particularly not to fight a fight that at least in Washington is perceived to be primarily a matter of regional concern.