It’s bad enough that Pentagon supervisors would sugarcoat intelligence reports on how the military is faring against any foreign adversary. But doing it in regard to assessments of the Islamic State when jihadists are expanding their attacks abroad risks the security of the U.S. and its allies.

The inspector general of the Defense Department is expanding an internal investigation of the U.S. Central Command on suspicions that supervisors revised intelligence reports on the Islamic State to present a more optimistic account of U.S. efforts. The New York Times reported months ago that Centcom intelligence accounts were being recast by supervisors; on Sunday it said the Pentagon’s inspector general recently obtained emails and documents to chart the revised assessments. More investigators have also been assigned to the case.

President Obama has ordered senior defense staff to root out whether the intelligence briefs had indeed been recast to paint a unduly rosy picture.

Unfortunately, we’ve been down this road before. Over-optimistic reports were issued in the 1960s to boost support for the Vietnam War. In 2011, the Pentagon was accused of providing excessively sunny assessments of security in Afghanistan as the U.S. was preparing to withdraw troops.

No one benefits from intelligence reports that are spun to lead the reader to a false conclusion. More important is that, in an ever-dangerous world, the facts are necessary not just for accuracy, but also for protecting lives.