General David Petraeus weighed in to the 2016 election Friday with a piece at the Washington Post. Though he never mentions Donald Trump by name, Petraeus is clearly talking about Trump when he writes that he is concerned with anti-Muslim political discourse playing into the hands of ISIS:

I have grown increasingly concerned about inflammatory political discourse that has become far too common both at home and abroad against Muslims and Islam, including proposals from various quarters for blanket discrimination against people on the basis of their religion.

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As policy, these concepts are totally counterproductive: Rather than making our country safer, they will compound the already grave terrorist danger to our citizens. As ideas, they are toxic and, indeed, non-biodegradable — a kind of poison that, once released into our body politic, is not easily expunged.

Setting aside moral considerations, those who flirt with hate speech against Muslims should realize they are playing directly into the hands of al-Qaeda and the Islamic State. The terrorists’ explicit hope has been to try to provoke a clash of civilizations — telling Muslims that the United States is at war with them and their religion. When Western politicians propose blanket discrimination against Islam, they bolster the terrorists’ propaganda.

Turning to the specifics of ongoing battles against al Qaeda and other extremists around the globe, Petraeus argues that the boots on the ground necessary to fight these threats will either be American or Muslim:

I fear that those who demonize and denigrate Islam make it more likely that it will be our own men and women who ultimately have to shoulder more of this fight — at greater cost in dollars and lives.

The position Petraeus stakes out in this piece is partially consistent with the Obama administration which has also consistently warned against playing into ISIS’ hands by attacking Islam too broadly. Obama visited a mosque in February and told his audience anti-Muslim rhetoric, “helps our enemies.” Petraeus also sides with the Obama administration in saying ISIS is a threat but not an “existential” threat. Where Petraeus differs with the Obama administration is in his use of the phrase “Islamic extremism” and in his statement that extremists like ISIS cannot be “contained.” He writes:

While Islamist extremist networks do not pose an “existential” threat to the United States in the way that Soviet nuclear weapons once did, their bloodlust and their ambition to inflict genocidal violence make them uniquely malevolent actors on the world stage.

Nor can they be “contained.” On the contrary, from Afghanistan before 9/11 to Syria and Libya today, history shows that, once these groups are allowed to establish a safe haven, they will inevitably use it to project instability and violence.