To eliminate bias, intentional or unintentional, you first have to be conscious of it. Without acknowledging that you are not treating similarly situated individuals similarly, the bias perpetuates, hardens and become impossible to eradicate. Police shootings? College admissions? No, I'm referring to coverage of the Democratic presidential primary race.

Earnest, enlightened editors and producers may think they are "following the story," but they are making it by affording excessive coverage, rather superficial coverage at that, to three white males, former vice president Joe Biden, Sen Bernie Sanders, I-Vt., and Beto O'Rourke.

My colleague Margaret Sullivan writes about the fallout from the Vanity Fair cover story on O'Rourke. "Somehow, despite a remarkably diverse Democratic field - which includes a record number of women, a gay man and several people of color - the B-Boys (that is, Beto, Biden and Bernie) - were off and running," she observes. From the Vanity Fair cover to the days of "Does Bernie still have it?" coverage to "Will Joe run or not?" you could easily go through a week of TV coverage and not know, for example, this was a historic election with six women (including four senators) in the race. Sullivan warns, "The news media undoubtedly was part of the equation. With more than 18 months to go before the 2020 election, the love and attention was not being dished out in equal measure."

It's actually worse than that. O'Rourke is behind Sen. Kamala Harris, D-Calif., in most polls. so even using the inane metric of covering the "leading" candidates almost a year before the race starts, the balance of coverage between the two is out of whack.

Well, there is all that excitement about Beto! Yes, the media frenzy has a way of creating anticipation - and then covering its handiwork. Anyone seen the excitement at a Harris rally? (Oh, her coverage is about shopping trips.) The media's job is to cover what is going on not only in white Iowa and at Penn State or among Sanders's almost entirely white audiences. Its job is to cover what the candidates are saying, not merely their fundraising hauls.

We have a race already covered by slogan - for or against Medicare-for-all? - the sort of dumbed-down coverage in which even the candidates getting excessive coverage escape close scrutiny of their positions and backgrounds. Has Sanders released his tax returns? He promised to nearly a month ago. Has O'Rourke been asked some specific foreign policy questions or even asked why he has so few policy positions? If they are going to lavish coverage on the three B's, at least make it more exacting.

Whether a product of racial and gender bias or just obsession with superficiality, presidential coverage of the 2020 Democratic primaries is shaping up to be just as misleading and imbalanced as was the coverage of the 2016 GOP primaries. With the exception of town halls - and kudos especially to Jake Tapper, who does an exceptional job - we once more risk selection of a candidate devoid of substance and artificially pumped up by shallow media coverage.

What is to be done? Let's suggest a few rules of the road. First, every day requires coverage of a mix of candidates, some well-known and some hardly known.

Second, until he wins something or makes news other than by showing up, the O'Rourke coverage needs to be scaled way back - and equal to that of similarly situated candidates in the top four or five in most polls. If he actually gives a substantive speech, by all means cover it!

Third, every candidate needs to be asked where his/her tax returns are; what their qualifications are for being commander in chief; what they plan to do about the debt; and when they've ever challenged the orthodoxy of their party (or base). In other words, start asking harder questions and interviewing others who know something about these candidates' backgrounds.

Fourth, if you are going to focus on a stereotypical quality - female boss from hell - you better look at more than one candidate to see if she's really so unusual.

Voters are ultimately responsible for learning about the candidates. Right now, however, the media isn't helping much if the goal really is to inform voters about their choices and test the candidates' mettle.

Jennifer Rubin writes reported opinion for The Washington Post.