So it wasn't a head-fake. What a relief. For VP Watch the thing we feared the most was waking up this morning and discovering that Obama had tapped someone we hadn't covered very much, or, disastrously, someone we hadn't covered at all.

Joe Biden's name emerged later than most, but once the pundits analyzed what he could bring to the ticket, his stock soared. Picking experience over regional appeal, "newness" and perhaps even personal relationship, Obama has faced his biggest deficit head-on -- and probably angered some of his supporters who thought he was changing the game. Biden is about as seasoned a Beltway guy as you can find in that stodgy town, but at least Biden comes with some eccentric flash. There won't be many dull moments covering Joe Biden.

Now for the bad news, which the McCain campaign wasted no time delivering to my inbox at 1:22 AM this morning:

There has been no harsher critic of Barack Obama's lack of experience than Joe Biden. Biden has denounced Barack Obama's poor foreign policy judgment and has strongly argued in his own words what Americans are quickly realizing -- that Barack Obama is not ready to be President.

There's even a ready-made video:

To be sure, these attacks sting. But deep down, I think the McCain campaign would have rather faced someone like Tim Kaine, someone who would allow them to continue their "inexperience" line full-throttle. As it is, Biden forces McCain to adjust that line of attack.

Importantly, Biden can act as a anchor to the soaring Obama, both on the stump and in the back rooms. Call it what you want: A degree of gravitas, of realpolitick, that the first-term phenom from Illinois very much needs going into the fall campaign. Had Biden been there earlier, and had Obama listened to him, I think the whole 200,000 German audience thing might have been nixed.

Which is not to say that picking Biden isn't a gamble. The best Obama can hope for is that voters see a balanced ticket, with each nominee shoring up the other's weaknesses. The worst that can happen is that voters see just how inexperienced Obama is. (Biden also has had a few unflattering things to say about Obama's Iraq positions.) Ironically, Biden himself once said in a campaign ad: "When this campaign is over, political slogans like 'experience' and 'change' will mean absolutely nothing. The next president has to act."