Rasmussen is out with an interesting new poll about media polarization and the presidential election. The cable network that each respondent preferred was a decent indicator of how that respondent plans to vote this fall, the survey showed.

The network that was most closely identified with a candidate was, unsurprisingly, Fox News. Eighty-seven percent of Fox News viewers said they’re likely to vote for presumptive Republican nominee John McCain. That result lines up neatly with a poll that showed that in the 2004 election, 88 percent of those who watched FNC supported George W. Bush over John Kerry — the demographic was Bush’s most loyal.

Viewers of the other two major cable news networks were also polarized, though not nearly to the extent FNC’s viewers were. Sixty-five percent of those who watch CNN plan to vote for Barack Obama, while 26 percent say they’re likely to go for McCain. Similarly, 63 percent of MSNBC’s viewers favor Obama, compared with 30 percent who say they’re planning to vote for McCain. (The results are about the same for those who rely on the broadcast networks.)

It’s hard to say just from these results the extent to which this reflects causation or just correlation — that is, whether people are choosing their news source based on their political preference or whether the news source is influencing their politics. It’s probably some mixture of both.

One amusing note, by the way — over at Newsbusters, a blog run by the Media Research Center, a right-wing press watchdog, there is a particularly interesting take on this. Blogger Noel Sheppard begins his post on the survey by asking, “Chicken and egg question: which came first, Obama supporters or pro-Obama media coverage?” And after quoting the actual poll data, which clearly shows that Fox News viewers are more partisan than those who watch other networks, Sheppard asked, “Did all the glowing, sycophantic, journalistically unprofessional coverage of Obama by CNN, MSNBC, and the nets create this support? Or are people just opting for news sources friendly to their candidate?” Seems like he left out an important part of the discussion, right?