We writers appreciate a semantic debate. As journalists and editors, we often argue over terminology, knowing our choice of words implies facts or judgments.

This is, indeed, a latent source of media bias. Straight-news stories call a politician an “isolationist” if he opposes war. Some outlets call the “March for Life” the “March Against Abortion Rights,” out of fear of suggesting pro-life people are “pro-life.”

So, we might have welcomed the repeated letters we've received from a dogged reader calling on us to stop using the term “progressive” to describe the Left end of the Democratic Party.

“The term ‘progressive’,” the writer tells us in at least three letters to Washington Examiner staff, “comes from the word ‘progress,’ which has positive connotations.” This, the letter contends, confuses the public, which knows what a “liberal” is.

This is a fair point. We would respond that “liberal” is also a positive term, related to “liberty,” a notion even more dissonant to the contemporary Left.

But we actually won’t engage in this specific debate, and we don’t, in fact, welcome these letters. Rather, we dislike them and reject them, because of who sent them.

Rep. Lamar Smith, R-Texas, in his capacity as a member of Congress and his capacity as co-chairman of something called the Congressional Media Fairness Caucus, apparently dedicates personal and staff time to picking semantic nits with journalists.

“As the Co-Chairman [sic] of the Congressional Media Fairness Caucus,” Smith wrote to one of our commentary writers last month, “I regularly look for examples of the liberal media’s bias and ways to counter it.” Our opinion page is hardly “the liberal media,” and so Co-Chairman Smith’s letter to us involved “bias inadvertently engaged in by conservative journalists.”

While Smith didn’t cite a particular offending article, we can only guess he was upset by a blog post headlined, “Democrats’ own research reveals unpopularity of progressive agenda in swing states.”

But the substance of that article and of the congressman’s semantic point are irrelevant. The issue here is that a member of Congress is telling journalists what to write. And he's doing it on congressional letterhead, too.

We welcome criticism from our colleagues and rivals, as we do from readers and academics. But we most definitely do not welcome editorial direction from officials of the federal government.

Rep. Smith, being fairly liberal (in the old sense of the word), is unlikely to propose legislation cracking down on media bias. Still, coming from a federal official, this could be chilling, if we were to pay it any heed. The federal government possesses overweening powers, and this means federal officials should keep their mouths shut on the subject of journalistic phrasing.

If a politician thinks he is being covered misleadingly, that’s one thing. Correcting an error is fine. Pushback to ensure an accurate record of events is fine. But the Congressional Media Fairness Caucus is not doing that. It has crowned itself a plenary arbiter of appropriate political terminology.

Maybe members of Congress think this is a fair turnabout because we tell them how to do their job. But it doesn’t work that way in a liberal democracy. Federal officials don’t get to tell journalists how we are to hold them accountable. Sue us for libel if you have a case. But calling liberals “progressives” does not rise to that level.

Lest we sound too adversarial, let us assure the congressman, that although this is a serious point, we make it as a reminder and without rancor. On Thanksgiving week, we let co-chairs and members of the Media Fairness Caucus know that we appreciate their continued readership, we welcome their briefings, and we're delighted to publish their op-eds. But, thanks very much, we'll pass on their edits.