One of the central dynamics of American politics in the last few decades has been the sorting of the parties, the way that the Republican and Democratic coalitions have become ideologically clearer and more narrow. There are some ways in which this has been a salutary development; for instance, if like many Americans you're a low-information voter, its easier to figure out which party to vote for than it once was. But while the GOP has become particularly unified—the northeastern liberal Republicans who once constituted a substantial faction within the party are all gone—there are still some moderate Democrats around, even in the South.
That means, among other things, that other Democrats have to put up with those Southern moderates doing things that would get them excommunicated if they were Republicans, like making bashing a Democratic administration one of the centerpieces of their campaigns. To wit, this new ad from Louisiana senator Mary Landreiu, who is facing a tough race this fall:
So there you have it, a solid minute of showin' 'em who's boss, standin' up against Washington, and givin' the Obama administration the what for. But I'm guessing the administration doesn't mind a bit.
They know this is all in the game. And you'll notice that the ad doesn't actually describe anything in particular Landrieu has done. It's a bunch of clips of her talking—talking on TV, talking at hearings, and so on. Landrieu is showing voters that she feels what they feel, and is angry on their behalf. If I were the administration, I'd say, "Talk all you want." This is just posturing, and it doesn't do any real damage if a southern Democrat postures against the Democratic party or a Democratic president. Because on balance, they'd rather have even a not-particularly-loyal Democrat in that seat than a Republican.
Now, there are certainly times when posturing turns to action, and real harm can be done. Some conservative Democrats in the past made a great show of being as critical as possible of Democratic goals, forcing the party to cater to them, and then siding with Republicans in the end (former Nebraska senator Ben Nelson comes to mind). But if all you're doing is striking a pose? Knock yourself out.