Federal Communications Commission Chairman Michael Powell on Thursday said the agency would not attempt to block Sinclair Broadcast Group’s plan to air “Stolen Honor: Wounds That Never Heal,” a documentary critical of Democratic presidential candidate Sen. John Kerry’s antiwar record, before the Nov. 2 election.

Word that Sinclair was planning to pre-empt regular prime-time programming to air a documentary that reportedly contends that Sen. Kerry’s public statements against the Vietnam War 30 years ago aggravated the ordeals of U.S. troops captured in the conflict has set off a firestorm of protest from Democratic lawmakers and the Democratic National Committee.

But Mr. Powell told reporters Thursday that the agency will not intervene. “I think we ought to be very clear up front that the FCC does not regulate programming editorial decisions by media companies,” Mr. Powell said.

The chairman said the only agency regulation that might come into play in the wake of a broadcast is an obligation that broadcasters provide equal time to candidates in federal election campaigns. “At least by press reports, that opportunity has been provided,” said Mr. Powell, apparently referring to reports that Sinclair has offered response time to Sen. Kerry.