While Fox & Friends has long been a home for some of the most vicious, misleading, petty, and dishonest attacks on President Obama, they crossed a new ethical line today by producing and airing what is essentially a four-minute anti-Obama attack ad.

The video -- opening with the text "Fox & Friends Presents" -- played lines from Obama's past speeches mixed with commentary from unidentified speakers and graphics purporting to show that Obama has broken the promises he's made since his 2008 campaign. The graphics were accompanied by loud, epic, scary music played over grainy video footage. Watch:

But while the video could be mistaken for a campaign ad on behalf of GOP candidate Mitt Romney, it wasn't. It was a segment produced by a show on a network that bills itself as “fair and balanced.” The network has continued to push the limits of its outright promotion of conservative politicians and policies, and Fox & Friends has been at the forefront. The show regularly acts as the communications arm of the GOP, attacking Democrats, promoting Republicans, and broadcasting GOP talking points, sometimes word for word. Co-host Gretchen Carlson has repeatedly advised GOP candidates how to promote their ideas in order to defeat their Democrat opponents.

Fox devoted 4,644 minutes of free airtime over eight months to the GOP presidential candidates during the Republican primary, a situation that led New York Times television critic Alessandra Stanley to note: “All the networks, broadcast and cable, are closely covering the campaign, but Fox News practically owns and operates it.” Former New York Times executive editor Bill Keller recently wrote that “the Fox News Primary probably did more to nominate Mitt Romney than New Hampshire or Michigan.” Fox's regular violations of journalistic ethics led Keller to conclude thatFox is "[Rupert] Murdoch's most toxic legacy."

On the morning after Mitt Romney clinched enough delegates to officially claim the Republican presidential nomination, Fox has launched its first anti-Obama attack ad of the presidential campaign.