Senior officials at U.S. Central Command manipulated intelligence reports, press statements, and congressional testimony to present a more positive outlook on the war against the so-called Islamic State, a House Republican task force concluded in a damning report released Thursday.

The report, written by the members of the House Armed Services and Intelligence committees and the Defense Appropriations subcommittee, confirmed more than a year of reporting by The Daily Beast about problems with CENTCOM analysis of the war against ISIS.

House Democrats, who conducted their own separate investigation, reached a similar conclusion as their Republican colleagues, finding that CENTCOM “insufficiently accommodated dissenting views,” Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, said in a statement.

The altering of intelligence reports, which included information that made its way into briefings to President Obama, was systematic, lawmakers found.

“There was a consistent trend that across four specific campaigns against [ISIS] in Iraq throughout 2014 and 2015, assessments approved by the J2 [CENTCOM’s Joint Intelligence Center] or leadership were consistently more positive than those presented by the [intelligence community],” the report found.

The lawmakers noted, for instance, that the CIA publicly portrayed ISIS as a more resilient and powerful organization than CENTCOM’s analysis—which was not publicly shared—suggested.

The lawmakers were limited in the amount of reporting they could review, but focused their attention on the period when ISIS expanded its reach to Iraqi cities like Fallujah, Tikrit, and Irbil in the Kurdish north. They found that senior CENTCOM intelligence officials gave a “deference to operational reporting,” including reports on the number of ISIS targets that were hit in airstrikes each day. But these incremental, day-to-day reports didn’t fully capture the trajectory of the overall war effort, which analysts said was not leading towards a U.S. victory over the terrorist group.

The Daily Beast had previously reported that CENTCOM intelligence leaders demanded significant alterations to analysts’ reports that questioned whether airstrikes against ISIS were damaging the group’s finances and its ability to launch attacks. Reports that showed the group being weakened by the U.S.-led air campaign received comparatively little scrutiny.

The congressional report confirmed those earlier allegations. The result of the altered reports was “analysis that was more positive regarding the capabilities of the [Iraqi Security Forces] and the progress of the fight against [ISIS]” than analysts felt could be justified.

“According to multiple interviewees, operational reporting was used as a justification to alter or ‘soften’ an analytic product so it would cast U.S. efforts in a more positive light,” the report found.

Lawmakers pinned the blame for the doctored reports—which prompted more than 50 analysts to complain to the Defense Department inspector general—on the top two leaders in CENTCOM’s intelligence directorate, Maj. Gen. Steven Grove, the head of the organization, and Gregory Ryckman, his civilian deputy. (Neither were mentioned by name in the report, but it makes clear that the problems coincided with their tenure and leadership.)

But for all the congressional report’s troubling findings, there is one important question that remains unanswered: Why did senior leaders alter the intelligence about ISIS? The report doesn’t answer whether Ryckman or Grove were acting on orders from higher up or suggestions of their leadership, whether changes in analysis were politically driven, or whether there was a climate that encouraged a positive assessment of the war effort.

The report doesn’t find any evidence that the White House ordered reports to be changed to present a rosier picture.

But Rep. Mike Pompeo, who was part of the task force, said the group believes that there was an unspoken understanding within the administration of how the war against jihadists was going and that drove decision makers within CENTCOM.

“The most senior leaders in Central Command and the J2 had a deep understanding of the political narrative the administration was putting forth,” Pompeo said in an interview with The Daily Beast. “The culture was one where you were rewarded for embracing that political narrative.

“The president was out talking about the same fight, the success of defeating the jihadist threat. The messaging from the [National Security Council] and the White House was all in one direction. So there is no alternative explanation for why they would behave this way they did,” Pompeo said.

Indeed, there’s little doubt that the rise of ISIS was a political embarrassment as well as a security challenge for the White House. It came one year after President Obama’s re-election, in a campaign that celebrated the wind down of the wars in Iraq and Afghanistan. In early 2014, Obama infamously described ISIS as the “J.V. team” among terrorist groups. U.S. troops left Iraq at the end of 2011 and, at the time, were supposed to be mostly out of Afghanistan by 2015.

“Despite nearly nine months of review, we still do not fully understand the reasons and motivations behind this practice and how often the excluded analyses were proven ultimately to be correct,” Republican Rep. Brad Wenstrup, a lieutenant colonel in the Army Reserve and member of the task force, said in a statement.

But Wenstrup noted the effects have been damaging regardless.

“We cannot win a war against ISIS with incomplete intelligence,” he wrote.

The Republican report attributed the problems at CENTCOM in part to a change in leadership and in the process by which intelligence reports are created. In the weeks after ISIS took control of Iraq’s second-largest city, Mosul, in June 2014, intelligence leaders were given a more direct say in how lower-level analysts’ reports were produced and then sent along to the military brass. That irked some analysts who, while outranked by the CENTCOM leaders, had been studying ISIS and other terrorist groups for years and thought their expert views weren’t being given full weight.

In May 2015, CENTCOM analysts formally complained to the inspectors general for the Defense Intelligence Agency and for the intelligence community, which passed the complaints on to the congressional committees. Seven months later, an internal survey of intelligence analysts revealed that 40 percent of respondents “had experienced an attempt to distort or suppress intelligence in the past year,” the report found.

“The survey results alone should have prompted CENTCOM and [intelligence community] leaders to take corrective action without other inducements. During interviews, however, multiple Intelligence Directorate senior leaders challenged the legitimacy of the survey results rather than taking responsibility for them,” the report found.

The amount of damage such misleading reports had on the Obama administration’s and the military’s overall understanding of the war on ISIS remains unclear. But the report noted that Ryckman and Grove had several secure conference calls with top civilian intelligence officials, including the director of National Intelligence, James Clapper, and that such access gave CENTCOM’s reports “outsized influence on the material presented to the president outside of formal coordination channels.”

“The impact was that you have a false signal being sent to officials,” Pompeo told The Daily Beast. “They had information what wasn’t true. It difficult to wind back and say what would have happened had they had different information.”

As part of a normal personnel rotation, Grove left CENTCOM’s intelligence directorate this summer and now is stationed at the Pentagon as director of the Army Quadrennial Defense Review Office. He has been replaced by Maj. Gen. Mark R. Quantock. Ryckman remains in the same position.

“U.S. Central Command has seen the Congressional Joint Task Force initial report and we appreciate the independent oversight provided,” Navy Cmdr. Kyle Raines, a CENTCOM spokesman, said in a statement to The Daily Beast. “We are reviewing the findings of the initial report; since the Joint Task Force investigation is ongoing, as is the [Defense Department Inspector General’s] investigation, we will refrain from further comment at this time.”

The Defense investigation is expected to be released by the end of this year.

The task force investigation in ongoing, Pompeo said, and he hopes to release a final report by the end of the year.