Fifteen years ago, Congress ended months of hearings and discussion, including horror stories from taxpayers caught in snares by unreasonable auditors, by passing an IRS reform bill. President Clinton signed it, and official Washington seemed to feel it could happily check an item off its to-do list.

Now it is clear that abuses at the almost autonomous agency charged with collecting revenue and enforcing tax laws don't end so easily.

We appreciate President Obama's tone of outrage at Monday's press conference toward reports that the IRS targeted tax-exempt conservative groups during the 2012 election season. In this nation, laws are to be applied equally, not used as political weapons for retribution. In addition to giving extra scrutiny to groups that had "tea party" or "9/12" in their names, the IRS reportedly went after groups dedicated to ending government overspending and debt, reducing taxes, understanding the Constitution, or that lobbied to "make America a better place to live," according to the Wall Street Journal.

Outrage isn't enough; both major parties should initiate investigations. If the allegations are found to be true, high-ranking people should, at the least, lose their jobs. Criminal charges should be considered. And perhaps Congress should revisit that 1998 legislation and find stronger ways to rein in a revenue service that still has a much larger stick than a leash. The IRS has tried to pin the blame on low-level workers in Cincinnati, but plenty of reasons exist to believe it spreads farther than that.

IRS official Lois Lerner first acknowledged the abuses and apologized during her talk at a conference on Friday. People familiar with the news business understand the significance of that. With weekend deadlines pending, and with lower media viewership and readership at the start of weekends, Fridays are good days to spring bad news that might, with luck, attract little notice. In this case, a Treasury Department inspector general's report into the matter is about to be released. No doubt, IRS officials knew it contained damaging information and they were looking for ways to safely get ahead of the story.

But a draft of that report says senior officials at the IRS knew about the extra attention given to tea party groups as early as 2011, according to the Associated Press. That is problematic, considering the man who was IRS commissioner in 2012, Douglas Shulman, specifically assured Congress the agency was not targeting conservative groups, who by then were growing suspicious of the questions the IRS was asking.

In a blog this week, Newsweek and The Daily Beast correspondent Megan McArdle speculated that the IRS was growing concerned with the proliferation of 501(c)4 groups claiming tax exempt status. Those exemptions are for groups promoting education and social welfare, not politics and elections. They may have decided on filters to use that would help them mine thousands of applications and zero in on those worth extra scrutiny. When told to stop this, they came up with new filters having to do with limiting government or taxes, or educating people about the Constitution.

She labels this an "incredibly stupid defense," and says, "There is no answer that does not ultimately resolve to 'political bias'. ... It's hard to think of any reasonable standard for extra review that starts with 'I didn't like their name.'"

Someone is bound to blame the Supreme Court's "Citizens United" decision for leading to these problems. That decision held that the First Amendment prohibits the government from restricting how corporations, associations or labor unions spend money on political causes. But nothing can justify the government attacking people on the basis of their political beliefs.