Have you ever had one of those “uh-oh” moments where you hit “reply all” on an e-mail without intending to? I have. And, apparently, so have the people at CBS News, and they have some explaining to do.

The question at hand involves how many questions the candidates get during debates. There’s always plenty of grousing about that from the second and third tier candidates – Rick Santorum did it again last night in South Carolina – but Michele Bachmann now has a much more solid case to make in complaining on this score. It turns out that CBS inadvertently sent a memo to somebody on Bachmann’s staff which seems to indicate that they planned to keep her on the back bench.

Numerous candidates from Rep. Michele Bachmann to Rep. Ron Paul complained about unfair treatment from the network, arguing that rival campaigns had received far more attention during the debate. The Bachmann campaign went so far as to release an email that they said spokeswoman Alice Stewart had “inadvertently received” from CBS earlier in the day.

In the email string, CBS News’ political analyst John Dickerson said that Bachmann was “not going to get many questions during the debate and she’s nearly off the charts,” a reference to the Minnesota congresswoman’s low standing in the polls.

After the debate Stewart said that CBS News was guilty of “a bias” against Bachmann.

“I inadvertently received an email where CBS made it clear that Michele was going to receive fewer questions than the other candidates. Clearly this is a problem,” Stewart said. “The debates are an opportunity for the candidates to share their views on the issues. This is an important issue for Congresswoman Bachmann. She’s a member of the House, the Foreign Intelligence Committee. She knows this issue unlike the other candidates on this stage and the email chain that I inadvertently received clearly indicates a bias on CBS’ part to limit the questions to Congresswoman Bachmann.

Here’s the pertinent portion of the e-mail in question so you can judge for yourself.

“Okay let’s keep it loose though since she’s not going to get many questions and she’s nearly off the charts in the hopes that we can get someone else,” Dickerson replied, apparently unaware that Stewart was copied on the email.

CBS is in a tough position here. On the one hand, if we’re to be honest about this, it’s obvious that the networks want to try to focus the most attention on the frontrunners who are in the most competitive positions. That’s where the news is, after all. But if you’re going to invite everyone to the debate, logic dictates that the whole idea here is to offer a broad range of ideas for the voters to consider, so everyone should – in theory – get equal time. It’s a tough balancing act, but CBS got caught with their hand in the cookie jar on this one.

Frankly, we’re running the clock down here before Iowa and New Hampshire, and I’ve already been thinking it might be time for the debate hosts to begin paring down the field. But even that’s a challenge. It would be nice to have less than eight people on stage so they might be able to get more than one minute per question. But where do you make the cuts? To be fair, you’d have to include anyone with clear frontrunner numbers in the polls. (Romney and Cain.) Money also plays a big factor, like it or not, so Perry is still in the mix on that count and may still make a comeback, particularly given his excellent effort in South Carolina. Newt is showing steady momentum with his poll numbers moving in the right direction. Ron Paul, while never near the top, consistently polls at or near double digits, so it’s hard to drop him. But could they reasonably slash Huntsman, Santorum and Bachmann and still claim to be giving the voters all of the information they need?

Either way, if you’re going to put your thumb on the scale, you need to be honest about it. CBS took another black eye on this embarrassing “tear away the mask” moment.