The morning-show wars went nuclear Tuesday, as reigning NBC superpower Today countered increasingly competitive ABC Good Morning America's aggressive week-long guest host stunt. GMA has imported former Today co-host Katie Couric for the week -- and Tuesday, Today launched its own offensive missile by hiring, as the special guest host of the day, Sarah Palin.

Both shows featured incendiary segments involving their guest hosts -- but not where expected...

Today teased the coming appearance of Palin by showing her "cramming" by reading a stack of daily newspapers. Then, in the first hour, host Matt Lauer interviewed her about her opinion of Mitt Romney as the apparent presumptive 2012 presidential nominee of the Republican party. "Anybody but Obama," was her boilerplate response.

But in the second hour, when her duties as host began, Palin got into unexpected hot water during a segment called "The Professionals," a sort of boiled-down The View in which panelists react to items in the news.

One such topic was a proposed new element for Facebook, where instead of "friending" someone, you could identify someone as an "Enemy" -- thereby bonding with others who share similar strong dislikes. The panelists, uniformly, were against it, but for different reasons -- and Palin's resentment of it as "I don't see anything good about this" was jumped on and challenged by "Professionals" panelist Donny Deutsch.

"Maybe they learned from politicians," Deutsch observed. "All we see from politicians is pure negativity."

Palin defended herself and her political colleagues, but Deutsch dug in.

"I was listening to your interview," he said, referring to Palin's chat with Lauer an hour earlier, "and your whole point was 'Anybody but Obama.' This is an extension of that."

Palin's reply: "I don't think saying 'Anybody but Obama' is necessarily such a negative thing."

Meanwhile, over on Good Morning America, Katie Couric was blending in more smoothly -- even playing along with a "tour the neighborhood" taped piece and visiting Madame Tussaud's Wax Museum, where she posed with a waxy likeness of Matt Lauer.

But in one segment, Couric presided over a story about a teacher and professional cheerleader accused of having improper relations with an underage male student. Her guests for the segment were NBC legal analyst Dan Abrams and Nancy Grace -- and their entire segment was a high-tension argument, with Abrams questioning Grace's reasoning, and Grace questioning everything but Abrams' parentage.

If I were to quote Grace, it would be less accurate to say "Grace said" than "Grace snarled."

And Couric, whether out of deference or self-preservation, just let the two of them go at it.

When it was over, Couric segued into the weather segment and Sam Champion. Champion chuckled and began by telling Couric, "We're just gonna throw some cold water up there."

Not necessary -- and perhaps not even desired.

There's no way you can up the ante, and the weaponry, in the morning show wars without generating a little heat.

GMA scored a temporary journalistic coup, and an undeniable in-your-face slap at NBC, by getting Couric for the week. Today, by giving Palin a day pass as a temporary member of the "liberal media elite," didn't do anything to strengthen its journalistic reputation.

But the morning news wars, especially this particular battle, isn't about journalism or credibility.

It's about ratings. And Palin is guaranteed to get attention in the short run.