Former IRS official Lois Lerner. (J. Scott Applewhite/AP)

The Federal Eye received lots of  feedback in recent days about an article analyzing the e-mails in which former Internal Revenue Service official Lois Lerner described conservative talk-show hosts as “__holes.”

In that piece, we noted that career federal employees are allowed to have political views, as long as those views don’t influence their work or affect elections. We also noted that Lerner’s comments represent only circumstantial evidence rather than rock-solid proof that she used her authority to silence conservatives.

Some readers objected to our rationale.

Another reader e-mailed: “Any good lawyer will tell you that circumstantial evidence is often more powerful than direct evidence. So saying something is just circumstantial evidence is not much of a defense though for some reason journalists think it is.”

To be clear, the point of last week’s article was not to suggest that authorities shouldn’t investigate Lerner for potential wrongdoing. It was to say that Republicans haven’t proven definitively whether the former IRS official used her position to slow down the proliferation of conservative advocacy groups.

Lerner headed an IRS division that dealt with tax-exempt organizations. There is no doubt that the IRS is supposed to enforce tax regulations, which includes examining whether groups are following the rules for tax exemption.

Did Lerner’s unit use inappropriate techniques to scrutinize such groups? The answer is yes, according to the agency’s inspector general, who said in a report last year that the IRS selected groups for review based on their names and policy positions.

The next question, then, is whether those actions were part of an effort to target conservative groups while going easy on left-leaning organizations. In other words, did Lerner’s political views — such as those expressed in her e-mails — cause her to become less than impartial in her work?

Democrats say the inappropriate treatment applied to groups from both sides of the political spectrum. They point to training materials that instructed employees to look for both progressive and conservative groups, and to the fact that the IRS ultimately pulled aside some left-leaning organizations — albeit a relatively small number. Also, there’s the self-described “conservative Republican” who told congressional investigators that he was the one who elevated the first so-called “tea party” case to Washington for extra scrutiny.

Nonetheless, many of the facts in this case look bad for Lerner. Her IRS division used inappropriate screening techniques that largely affected conservatives. She was a registered Democrat who used offensive terms to describe firebrand right-wingers. She expressed a desire to work for an advocacy group founded by President Obama’s allies. And she invoked her Fifth Amendment rights instead of testifying before Congress about her involvement in the targeting behavior.

Regardless, that’s all circumstantial evidence. It makes Lerner a prime candidate for investigation, and it’s great campaign fodder for the midterm elections, but it does not prove that she violated the rules of professionalism by trying to hinder conservative groups. Republicans need direct evidence to confirm that theory, which is part of the reason they want an independent prosecutor to look into the case. It’s also why they are so frustrated with Lerner’s missing e-mails.

For what it’s worth, the Justice Department has declined to appoint a special prosecutor to investigate the targeting matter, saying its own staff can handle the review impartially.