In case you didn't notice, Monday was Tax Day, which means it's also the second anniversary of one of the tea party movement's biggest moments, April 15, 2009, when dozens, if not hundreds, of well-attended protests were held around the country.

It was a coming-out party of sorts for the movement. No one really knew what the tea party was at that point, and, as momentum built toward the Tax Day rallies, details began to emerge regarding just who they were, and who was organizing them.

Today, the movement seems to be dwindling.

Tax Day, 2011, came and has largely gone without the same kind of massive, irate throngs in every state and major city. We can attribute that, to some degree, to the scheduling shift of Tax Day to April 18 and the movement's consequent dispersed focus, holding rallies on Friday, Monday, and over the weekend, rather than on just a single day. But you can't deny that, as an activist movement, the tea party has lost some momentum, attendance-wise.

A Michele Bachmann rally in South Carolina Monday drew a measly 300 people. A few weeks ago, maybe a couple hundred showed up to a Capitol Hill protests held by Tea Party Patriots, the nation's largest tea party membership group, which once estimated its membership at over 15 million. It was hard to tell how many were there to participate and how many were there to spectate and the tea partiers were almost outnumbered by the reporters.

A Virginia tea party activist told me recently that members of his group are spread too thin. "We're kind of saturated right now," he said, explaining that different people and groups ask them to do too many things. He showed me a few of the emails sent around to members, asking various things of them. It's a problem, he said.

As the activist infrastructure has built up, so have the demands on individual activists. With the initial fervor wearing off, it makes for a tired bunch of crusaders.

And yet the tea party seems to have accomplished its main goal: bending the will of the Republican Party.

Republican politicians widely cater messages and platforms to a tea party audience. Listening to what is said by Republican presidential contenders, House members, and candidates for office, it's tough to argue the tea party hasn't left its mark. It's taboo not to talk about drastic cuts to federal spending, whether or not one has a plan for the specifics.

During the midterms, Republican candidates met with tea party groups, seeking their approval. It became impossible to distinguish a "tea party" candidate from a regular Republican.

That effect has carried over into 2012. The Tea Party Express will partner with CNN to host a GOP presidential debate, and the movement's influence will finally be institutionalized in the 2012 primary contest.

Perhaps most significantly, Washington is now engaged in a serious discussion of how to reduce spending levels over the long term. While President Obama rejected the House GOP's drastic 2012 budget proposal out of hand, it's safe to say he was forced by November's results and the tea-party-fueled GOP House takeover to propose a big number, $4 trillion, of cuts from the deficit over the next 12 years.

The tea party movement can legitimately take some credit for that. We'll find out, as the 2012 election approaches, just how much gas is left in the tea party's tank. It's likely that the GOP 2012 contest and the tea party's rallies will blend into one continuous political event, with candidates taking turns on stage and with lots of people turning out.

But the movement is in an ironic place now. Without an election this year and with attendance tapering off, it's also become institutionalized as a fixture in American politics, having possibly swayed enough 2012 candidates to preempt the presidential primary from even being a flashpoint in the GOP's identity.

Apparently what we're seeing now is what victory looks like.

Drop-down image credit: AP