The Internal Revenue Service’s targeting of conservative groups is appalling. But an audit from the Treasury Department’s inspector general for tax administration shows that the IRS’ recklessness in the last few years hasn’t been limited to that politically driven abuse of its revenue-collection duty.

Saturday’s Washington Post published troubling details of that audit, which will be officially released today. Among them:

The IRS spent nearly $50 million on at least 220 “conferences for employees” over a three-year period starting in 2010.

That wording makes those meetings sound work-related. Yet the IG’s audit makes them sound like a stunning waste of employees’ time — and taxpayers’ money.

Among the “conferences” cited is an August 2010 gathering in Anaheim, Calif., for more than 2,500 IRS staffers. Approximately $3.2 million from the agency’s “enforcement budget” helped fund that $4.1 million extravaganza.

From the Post: “During the conference, employees watched two training videos that cost at least $60,000 to produce, according to the audit’s estimates. The first video is a ‘Star Trek’ parody and stars division employees discussing how they might identify and address allegations of tax fraud. Aides briefed on the audit said that employees paid for the ‘Star Trek’ uniforms they wear in the video but that the agency paid for the construction of an elaborate mock-up of the bridge of the Starship Enterprise.”

And: “The second video stars some of the same employees learning how to dance ‘The Cupid Shuffle’ from a 2007 song by the performer Cupid. As other employees learn the dance moves, one female employee comments, ‘They don’t pay me enough to do this.’ ”

So why are we paying her, or anybody else, to attend such silly “conferences”?

This squandering of public money, while infuriating, isn’t nearly as chilling as the realization that the IRS, under a liberal president, singled out conservative organizations. Additional revelations have been emerging in the targeting scandal over the last few weeks.

Meanwhile, Lois Lerner, director of the IRS’ exempt-groups division, has pleaded the Fifth Amendment rather than answer questions from federal lawmakers.

Thus, it appears that a special prosecutor will be needed to get to the truth of the case, which represents a fundamental violation of the public’s trust that our tax system will be implemented in a non-partisan manner.

And a Quinnipiac University poll released late last week found that 76 percent of Americans surveyed favored an independent counsel to investigate that shocking IRS misconduct, with only 17 percent opposed. Even Democrats backed the special-prosecutor option by a lopsided, 63-30 percent margin.

Troubling questions also persist about what went wrong before, during and after last 9/11’s terrorist attack on the U.S. diplomatic facility in Benghazi, Libya. The Justice Department’s sweeping — and secret — surveillance of journalists demands answers, too.

But while those high-priced IRS “conferences” aren’t as alarming as the other three scandals now dogging the Obama administration, they pose serious questions of their own.

And no, IRS officials can’t evade responsibility by doing “The Cupid Shuffle” — or by saying, “Beam me up, Scotty.”