Linda Douglass, the former CBS and ABC News correspondent who joined the Obama presidential campaign and later the administration, has emerged as the point person in the White House pushback against "disinformation" regarding national health care.

She's one of several former journalists who are part of Team Obama, and her experience illustrates the problem that liberally inclined journalists face when they choose to enter politics. (Although a few Republican reporters have joined GOP administrations, this is mostly a Democratic problem, given the left-leaning sympathies of most journalists.) The problem is this: As both a trained reporter and a government official, how does one flack for the boss while ignoring the questions any journalist should ask?

Recently, Douglass undertook to debunk a video going around the Internet showing Barack Obama, before he became president, endorsing a single-payer national healthcare system. "I happen to be a proponent of a single-payer universal healthcare plan," Obama said at a conference in 2003, as he was beginning a run for the U.S. Senate. "That's what I'd like to see."

A viewer might reasonably conclude that, at least in 2003, Barack Obama was a proponent of a single-payer universal healthcare plan. Not true, said Douglass. In a video posted on the White House Web site, she explained that there is a lot of "disinformation" going around these days about healthcare reform. Opponents of reform have been "taking sentences and phrases out of context" to create a "false impression" of the president's words.

"There are people out there with a computer and a lot of free time, and they take a phrase here and there they simply cherry-pick and put it together," Douglass said, "and make it sound like he's saying something that he didn't really say."

A few years ago, Linda Douglass the journalist might have asked just how Obama's 2003 declaration of support for single-payer health care was taken out of context. Now Douglass the White House spokesperson didn't even address the question. And she offered no evidence to suggest that the meaning of Obama's words had somehow been distorted.

Instead, Douglass played a clip of Obama as president, at an AARP forum in July, pledging that people who like their current insurance will be allowed to keep it.

A few years ago, Linda Douglass the journalist might have asked what caused the president to change his mind and why the American people should take seriously what he says now. But Douglass the White House spokesperson had nothing to say about that.

Douglass had more to contend with than just Obama's words from 2003. In 2007 it's on that Internet video Sen. Barack Obama said, "I don't think we're going to be able to eliminate employer coverage immediately. There's going to be potentially some transition process."

A viewer might reasonably conclude that, at least in 2007, Obama wanted to eliminate employer coverage. There's simply no question that, when it comes to health care, Obama is saying different things today than he said just a few years ago.

Interviewing Douglass on CNN, "Reliable Sources" host Howard Kurtz pointed out that Obama had "a different position when he was a senator, and that's legitimate to throw out there."

"He didn't have a different position when he was a senator," Douglass insisted. But she still didn't offer any evidence to support her contention.

Why would a former reporter a line of work that should include a healthy dose of skepticism stick so blindly to the party line? "If you were still a journalist, you would be sitting in this seat, you'd be asking many of the same questions that I am," Kurtz told Douglass. "Instead, you're a saleswoman. You have to sell the president's plan, right?"

Douglass replied that she believes deeply in the Obama healthcare makeover. She recalled her years as a network reporter, covering the failed Clinton healthcare initiative. "The special interests just crushed the effort," she said with a note of regret in her voice.

Now Douglass, the true believer, is working to make sure that the latest makeover succeeds. No longer a journalist, she's free to be as partisan as she likes, but she is squandering whatever reputation she built earlier in her career. That's the dilemma of the journalist-turned-spokesperson. The minute you step over to the other side, you lose the credibility that got you the job in the first place.

Byron York is chief political correspondent for The Washington Examiner.