We tend to think all mass murderers are mentally ill to some extent, and evil. Just because Donald Trump suggests mental illness plays a part in America’s spate of mass shootings does not mean it isn’t so.

We also think twisted minds are impressionable minds, especially in this day and age of social isolation in an increasingly godless nation.

But those minds can be impressed by all manner of speech and all shades of politics. To what degree inflamed rhetoric contributes to someone gunning down masses of people is a big unknown.

How much was the El Paso shooter affected by white supremacist demagogues? How much was the Dayton, Ohio, shooter affected by his expressed animus toward Joe Biden and his social media pledge to Sen. Elizabeth Warren?

Much of the news media and many leftist politicians have reported or said little about the Dayton shooter’s Twitter rants. To be sure, the limited Dayton written record on politics is nothing when compared to the extensive El Paso manifesto and evident prejudice against Mexicans and Hispanic Americans.

Writing online for Commentary Magazine, Noah Rothman notes: “It’s not unreasonable to expect terrorists targeting strangers in acts of mass violence to have some ideological motivation. Nor is it arbitrary to identify and explore a shooter’s radical beliefs in the effort to stigmatize them and prevent copycat attacks. No one should be shocked to learn, though, that disturbed individuals who carry out perverse acts of terror adhere to disjointed and illogical doctrine.”

Rothman notes that the same news media that rejects the Dayton shooter’s political record as too scant to even mention, has had no such trouble linking Trump and conservatives to previous shooters based on the thinnest of evidence.

This “newfound principle” to distinguish between a long written record as opposed to a few Tweets “seems only to be an outgrowth of the desire to avoid muddying a useful narrative in the age of Trump.”