Hilariously low turnout---especially compared to left-driven events as of late---at various Tax Day events held by the Tea Party is causing some to declare the phenomenon over.  Rachel Maddow covered it:

Paul Waldman at the Prospect covered it, citing Michael Scherer and Jed Lewison at Daily Kos. There's a couple of theories abounding about why the Tea Party has basically lost all its momentum.  Rachel believes it's because they won over the Republican party, and so there isn't any need for them.  Paul agrees, and also suggests the primary is distracting them from hating on Obama, er, obsessing over weird theories about taxes and the Constitution.  Scherer simply thinks the brand has been watered down.

I have a different theory, though I think that Rachel and Paul are right that part of it is that mainstream Republicans are dropping the words "Tea Party" a lot, and making them feel all special.  But that points to the larger reason that the Tea Party has fizzled out.  Remember, the "Tea Party" is just a fancy new name for the same old conservative base.  And they are culture warriors first and foremost.  And by "culture warriors", I don't mean it in the narrow way used by the Beltway press.  The culture war is about more than butt secks and abortion.  The culture war is about declaring conservatives to be the only Real Americans, and denouncing the erosion of a hierarchal society where women, gays, and racial minorities know their place.  Pretty much all Tea Party issues go back to this.  As the budget battle demonstrated, this wasn't ever about an actual balanced budget, since the amounts that were discussed were relatively minor and real cuts that would get us to a budget balance (say, to defense) were never considered.  The items were culture war stuff, mostly attacks on groups that Tea Partiers count as not Real Americans.*

The reason I think they're petering out is they won an election and now have confirmed that they're still the official owners of the country.  So they're packing it in.  After all, rallying is hard work!  All they wanted was reassurance that Barack Obama isn't a sign that a new, more inclusive America really is going to eclipse the America they know and love, where mean, ignorant white men run everything and everyone else has to just put up with it.  The new slew of governors and congressmen are very comforting to them---a sea of white faces perched atop ugly ties.  Now that they've got that, they feel reassured, and are going home, content with the knowledge that the Republicans are going to fuck someone they hate over.  The panic attack caused by Democrats controlling three branches of the government has ended now that Democrats don't have that power any more.  And while Tea Partiers still don't like Obama, they're increasingly convinced his election was a fluke. 

I honestly don't think it's much more than that. What will be interesting going forward is seeing how Tea Partiers react when it becomes clear that in fact the Republican wins were the fluke, and that the demographic changes to this country they fear are still coming to pass.  Since so many states are considering laws that are basically flouting the Voting Rights Act of 1965, however, they may be able to hold on to the illusion that they're the only people who really count for a little longer.

*Even though 99% of straight women use contraception at some point in their life, part of the reason I think that attacks on contraception have become politically salient when pandering to the Tea Party is the average age of the Tea Party.  It's easier for Tea Party women to reconcile their own lives with these attacks because most of them have passed the age of needing contraception.  Which isn't an attack on post-menopausal women across the board, so please put down your keyboards.  Just noting that the average age of the Tea Party makes younger people attractive targets for the Tea Party.