It all seemed to add up. At least it did then.

The Internal Revenue Service, according to outraged Republicans and many media accounts at the time, targeted tea party organizations and other conservative nonprofit groups that were seeking tax-exempt status between 2010 and 2012. Critics said the tax agency had subjected the targeted groups to extra scrutiny, questioning and long delays, largely because their names suggested they would be political opponents of the Obama administration and the Democratic Party.

The allegations formed one of the best-known scandals of former president Barack Obama's administration and led to months of congressional hearings, official investigations and damning news coverage.

Now, it seems, it wasn't so simple.

A report released Thursday by the Treasury Department's inspector general for tax matters indicates that the IRS also singled out nearly 150 organizations whose names suggested they were affiliated with liberal organizations. Without specifically characterizing the politics of the groups, the report said the IRS initiated reviews when applicants' names included words such as "occupy," "progressive" and "green energy" between 2004 and 2013.

The same Treasury watchdog had said in 2013 that the IRS reviewed about 250 conservative-sounding groups, with names that included words such as "tea party" or "patriot." That report fueled the scandal narrative: "This was a targeting of the president's political enemies, effectively, and lies about it during the election year so that it wasn't discovered until afterwards," Rep. Darrell Issa (R-Calif.), the chairman of the House oversight committee, said at the height of the controversy in 2013.

The new finding suggests Republicans and the media provided an incomplete or even misleading account of what the IRS was up to when it was reviewing political organizations that sought tax-exempt status. While not of the order of the news media's credulous (and flawed) reporting about supposed weapons of mass destruction in Iraq before the U.S. invasion in 2003, the report offers a check on the prevailing narrative of the time.

It may also offer a measure of vindication to Obama, at least according to one of his senior advisers.

"The Obama administration was often accused of Nixonian wrongdoing," Eric Schultz, the former president's spokesman and a deputy White House press secretary under him, said Thursday. "At some point, I lost track of how many Watergates we had. But we live in an environment where the more hyperbolic your allegation is, the more likely it will get headlines, no matter its veracity. This report substantiates our argument that our White House did not politicize the IRS, but those allegations, A1 material at the time, have lived online for four years and now that the public has moved on, they're proven false."

The original allegations were given broad play by mainstream media outlets, including The Washington Post. In May 2013, it was the subject of thousands of news articles and TV segments. A CNN reporter framed it this way at the time: "The smell of scandal has given this administration, suddenly, the appearance of having been thrown off balance."

The story line was perhaps most eagerly embraced by conservative media outlets, which cited it as evidence of corruption by Obama and the IRS. The characterization of one-sided treatment persists; Breitbart News reported last month that the Department of Justice was declining to investigate "IRS suppression of tea party groups" (Breitbart's editor did not return a request for comment).

To be sure, the head of the IRS' tax-exempt organizations division, Lois Lerner, contributed to the furor at the time. As the controversy began in early May, Lerner apologized to tea party and conservative groups for unwarranted scrutiny; she also cited the Fifth Amendment and declined to testify before Issa's committee.

"We were deliberately kept in the dark," said Kurt Bardella, Issa's spokesman at the time. "If the IRS had said 'We don't know,' it would have been better than saying nothing."

Gray areas did emerge during the controversy. In a front-page story in July 2013, the New York Times reported that a "more complicated picture [was] now emerging," based on investigations by Congress and the IRS that showed that liberal groups had been subjected to long delays in approving their applications, too. The Post reported a similar story a few days later.

By that time, however, the burst of news coverage of the issue may have done its damage. When the story first gained traction in mid-May, Obama's approval rating in a CNN poll was 53 percent. By mid-June, it had slumped to 45 percent in the same poll, a level it stayed at for many months.

The issue might have become part of what Dartmouth political scientist Brendan Nyhan has called the "scandal attention cycle" — the rapid surge of attention as reporters race to cover an issue followed by a similar decline as the news media loses interest. "The problem is that it often takes time for the full set of facts to come out," Nyhan has written. "By that time, the story is old news and the more complex or ambiguous details that often emerge are buried or ignored."

Indeed, the original claims by Republicans were widely reported "without much investigation," said DeWayne Wickham, dean of the journalism school at Morgan State University and a former columnist for USA Today.

News organizations, Wickham said, "do too much repeating and not enough reporting. As a result, journalists often use the work of other journalists as the primary source of the news they report. In the case of the IRS story, this problem was compounded by an obsession that a lot news organizations have with proving they are balanced in their coverage of the warring between the political right and left."

The lesson journalists can learn is to be much more skeptical of what seems clear-cut, said Lisa Shepard, a media ethics professor at the University of Arkansas. "I've learned from studying the fake-news phenomenon in depth that if something taps into your, 'That's outrageous' button, you need to slow down [and] go deeper into exploring that it might not be true," she said.