Anyone over 40 will remember Joe Isuzu, the smarmy pitchman who, in a series of 1980s car commercials, lied his way into America’s heart. The Joe Isuzu character, played by David Leisure, was an ingenious creation of comic advertising—a pathological liar who somehow wound up as the spokesman for a major car company. Looking straight into the camera with dimwitted confidence and a greasy smile, he would make ludicrous claims (Isuzu trucks are “so inexpensive you can buy one with your spare change!”) that would hastily be qualified with clever subtitles (“if you have $6,189 in quarters”). It was all good fun: everyone knew Joe was lying; no one took him seriously.

Fast forward to 2014: White House Press Secretary Jay Carney, once a respected journalist, has been morphing before our very eyes into “Jay Isuzu.” I refuse to call Carney a liar. But it’s clear that when he’s called upon to defend the indefensible, he stubbornly resists telling the truth. And with the White House press corps rediscovering some journalistic skepticism after years of credulous slumber, Carney is having to defend the indefensible with increasing frequency. The result isn’t pretty: Carney, like Joe Isuzu, is not being taken seriously.

Carney’s credibility hit a new low this week. Thanks to a lawsuit by the watchdog group Judicial Watch, the White House was forced to release documents that shed light on the Benghazi scandal. One was an email circulated among a White House team, including Carney, that was preparing then-U.N. Ambassador Susan Rice to discuss the Benghazi attacks on the Sunday talk shows. According to the email, Rice should “underscore that these protests are rooted in an Internet video, and not a broader failure of policy.” And, of course, when Rice did appear on those talk shows, she infamously blamed an anti-Muslim internet video for a spontaneous protest in Benghazi.

That protest, according to Rice, got out of control, which led to the deaths of four Americans. As we would eventually learn from Fox News (along with the tiny number of mainstream reporters who weren’t busy yawning), there was no protest, spontaneous or otherwise, before the Benghazi attacks. CIA and State Department personnel in Libya knew that almost immediately, and had promptly reported it back to Washington.

The newly released documents seemed to confirm what should have long been obvious: The White House, in the midst of a reelection campaign, saw Benghazi as a public relations problem. The boast that Al Qaeda was “on the run” was important to the president’s campaign. They desperately wanted to avoid the impression that they had been caught off-guard — on a 9/11 anniversary, no less — by a successful attack from an Al Qaeda affiliate. It would have been harder to blame the administration for failing to anticipate that an obscure internet video would trigger a spontaneous protest that would get out of control. Who, after all, could have anticipated that? That scenario, of course, was untrue, which begs the question: Who was behind the administration’s insistence that the video was to blame? Carney has long maintained that the administration’s “blame the video” talking points were based on information supplied by the CIA. Former CIA Deputy Director Mike Morrell, however, has debunked that. So who, as Greg Gutfeld has been asking incessantly, pushed the video? It appears now that the White House itself pushed the video, for political reasons.

Carney was forced to defend the new revelations at Wednesday’s White House briefing. Under intensive questioning from ABC News’s Jonathan Karl, Carney insisted that the talking points in the White House email — the ones exhorting Rice to blame the video — related not to Benghazi, but to protests that had occurred elsewhere in the Arab world. That seems rather dubious, given that those same talking points stress the need to bring “people who harm Americans” to justice: No Americans were harmed at any of those protests. Also, the White House released the email in response to a demand for documents relating to Benghazi. If the email did not relate to Benghazi, it presumably would not have been released.

Carney continued to insist that Rice relied on CIA talking points when she discussed Benghazi on television. But the CIA has denied ever blaming the video for the Benghazi attacks. So where did Rice get the idea to blame the video for Benghazi, if not from the White House prep team? Carney had no coherent answer.

Townhall’s Guy Benson did an excellent summary of Carney’s cringe-worthy performance at Wednesday’s briefing, including video clips. Depending on which side you’re on, it’s either agonizing or amusing to watch Carney spit out a procession of preposterous statements with a straight face. And when not even he can manage a straight face, he masks it with the sneer that is fast becoming his trademark.

Carney’s hapless tap-dancing act is becoming a daily event, as he struggles to explain away a relentless parade of “phony scandals.” It is strange to think that Carney was once Time magazine’s Washington bureau chief, a vaunted position at the highest echelon of the mainstream media. More than any press secretary in recent memory, Carney has squandered the credibility and reputation that he brought with him to the job. It makes one wonder how many other mainstream journalists could flip so seamlessly from aggressive, skeptical reporter to partisan hack. I don’t think it’s plausible that Carney has changed so dramatically in just a few years. It’s more likely that when Carney was supposedly an objective reporter, he was secretly the same person he is today — deeply partisan, deeply biased.

As a conservative, I suspect that mainstream journalists are generally cut from the same cloth as Carney, and would, like Carney, readily trade their “lofty journalistic ideals” for the chance to flack for a liberal administration. And that attitude, I believe, finds its way into the journalism they produce before they get the call to join Team Obama — or Team Hillary. If the mainstream media are indeed full of Jay Carneys waiting to happen, then conservatives are right to distrust them.

Under Jay Carney, the position of White House press secretary has become more partisan than ever. As Carney once again showed on Wednesday, he is intent not on disseminating the truth but on obstructing its dissemination. This raises a question: Why should taxpayers pay for a spokesman whose job is not to inform the public, but rather to spout partisan propaganda on behalf of the president’s party? Why should Republican taxpayers have to pay for a Democrat to constantly insult them, and why should Democrat taxpayers have to pay for a Republican to constantly insult them? Shouldn’t the president’s party, be it Democrat or Republican, pay the press secretary’s salary?

David B. Cohen served in the administration of President George W. Bush as U.S. Representative to the Pacific Community, as Deputy Assistant Secretary of the Interior, and as a member of the President’s Advisory Commission on Asian Americans and Pacific Islanders. He is the author of Left-Hearted, Right-Minded: Why Conservative Policies Are The Best Way To Achieve Liberal Ideals.