Jeremy Scahill, an investigative foreign correspondent whose first documentary, “Dirty Wars,” opens Friday, writes for The Nation and achieved his biggest success with “Blackwater,” a best-selling book critiquing security contractors hired by the George W. Bush administration. Neither of which keeps him from being labeled a right-wing stooge by detractors.

“Most of my hate mail nowadays comes from liberals, not conservatives,” he said.

This is because Mr. Scahill has also been an outspoken critic of President Obama. Specifically, he disapproves of what he describes as the administration’s efforts to “normalize and legitimize” targeted assassinations — drone-executed and otherwise — Special Operations raids and other covert military practices that blur the battle lines of the war on terrorism.

“Dirty Wars” is his latest salvo. In the film (his book with the same title came out in April), Mr. Scahill investigates several American strikes that killed civilians with no apparent ties to terrorist groups, beginning with a February 2010 raid in the village of Khatabeh, Afghanistan, that killed several members of a family. An Afghan police chief and three women were among the dead. (The United States first denied and then acknowledged its role in the deaths.)

Along the way Mr. Scahill suggests that such acts are radicalizing Muslims both obscure — a man in Khatabeh talks about wanting to become a suicide bomber — and well-known, like the American cleric-turned-Qaeda firebrand Anwar al-Awlaki, who was killed by drones in September 2011. “We are encouraging a self-fulfilling prophecy,” Mr. Scahill said. “We are making more new enemies than we are killing actual terrorists.”