When the credentialed blogger corps whips out its laptops to chronicle the Democratic National Convention, its members will have a lot more in common than HTML prowess.

A glance at the 120-strong list of credentialed blogs (encompassing, the DNC tells us, about 700 bloggers) reveals a strong ideological bent — excluding nonpartisan sites such as BeliefNet and some state political sites. Not surprisingly, it’s to the progressive or left-of-center side of the spectrum.

The DNC told us that this list is representative of the blogs that applied for credentials. Without a list of applicants — something the DNC wouldn’t provide, citing the same privacy standards applied to other media organizations’ applications — it’s impossible to tell how many blogs of differing viewpoints may have tried to get in but got rejected for whatever reason.

The application for the DNC’s State Blogger Corps — a new program to seat bloggers who cover state and local politics with their home-state delegation — might have scared off some libertarian or right-of-center applicants with this statement: “Bloggers may also provide examples of posts that make their blog stand out as an effective online organizing tool and/or agent of change.”

“Change,” in this election cycle, tends to be code for “supports Obama.” That’s fine if you’re looking to credential a corps of party cheerleaders. But when compiling a group of citizen journalists, the standards should be competency, ethics and track record — what you’d expect from any other journalist.

“When we were at the media day,” one local conservative blogger told us, “I asked specifically how much of a role ideology would play in the credentialing process and the gentleman guiding us through the orientation simply refused to answer.”

The case over at the Republican National Convention is hazy, as well. Another blogger told us that he believes he was denied RNC credentials because of his vociferous opposition to John McCain, which is also impossible to confirm.

The RNC told us that invitations had been sent out to 200 blogs representing a “dynamic cast,” including left-leaning powerhouses Wonkette, The Huffington Post and BlogHer. But there’s no list available to peruse, as the RNC told us RSVPs were still coming in.

The speculation goes on and on, but it’s true that independent bloggers — whose work is studied by credentialing committees at the very least to determine a blog’s legitimacy and staying power — are much more likely than traditional media to have their ideology taken into account when seeking press access. That’s in part because there are no safeguards (such as a big media organization in their corner) to ensure this isn’t taken into account. Are bloggers classified as activists? Journalists? A bit of both?

You can’t imagine the DNC banning Fox News from walking in the door, or the Republican National Convention shutting out National Public Radio. Ideological screening of the media is just not something you do in a society that cherishes freedom of the press.

The same neutrality should apply when credentialing bloggers to cover political conventions. Surely we don’t want a system that seeks to use bloggers as propaganda mouthpieces as opposed to citizen journalists reporting on the conventions for their Web audiences.