Conservatives are fond of criticizing the mainstream media for presenting the news with a significant liberal bias – and recent data suggest that such critics may have a point.

Journalists are four times as likely to identify as Democrats than as Republicans, according to a survey of journalists by Indiana University journalism professors Lars Willnat and David Weaver. When asked their party affiliation, 7 percent said they were Republican, compared with 28 percent Democrat. Fully half (50 percent) identified as independent, with “other” accounting for the remaining 15 percent.

While an increasing number of journalists are identifying as independents, the decline for Republicans has been steep since 2002, when the makeup was 36 percent Democrat, 18 percent Republican and 33 percent independent.

Among those journalists inside the Beltway in Washington, D.C., who are responsible for most national political coverage, the slant is greater. More than 90 percent of Washington correspondents vote for Democrats, and an even greater portion contribute to Democratic politicians or liberal-leaning political action committees, Tim Groseclose, George Mason economics professor and author of “Left Turn: How Liberal Media Bias Distorts the American Mind,” told the Washington Times.

“There’s something in the DNA of liberals that makes them want to go into jobs like the arts, journalism and academia more so than conservatives,” he said. “Even if you’re just trying to maximize profits by offering an alternative point of view, it’s hard to find conservative reporters. So it’s natural the media is more liberal.”

This bias is not always overt, and some journalists might not even be aware that their political beliefs are coloring the nature of their stories. And even when stories are not slanted, bias might reveal itself in the kinds of stories that are selected – and not selected – for publication.

Findings of journalists’ lopsided party and ideological leanings are not really news, as numerous other surveys have demonstrated that most Americans are aware of various media biases, but they serve as a reminder that, for a free republic to endure, citizens must remain engaged in the political process and view the news with a critical eye, never taking sources for granted and always seeking the truth – just as journalists are supposed to do.