Nevada was a hotbed of Tea Party activity in the 2010 midterms, but in the weekend's GOP presidential caucuses, the Silver State activists' least favorite candidate, Mitt Romney, trounced the field. In Colorado — which, along with Minnesota and Missouri, picks its preference for the GOP presidential nominee on Tuesday — the Tea Partiers who dominated the political scene two years ago are no longer holding many rallies. And now an Ohio Tea Party leader tells The Daily Beast that while the movement may have been a giant killer in 2010, it's "dead" and "gone" this year. What happened? Here, four theories:

1. Tea Partiers never settled on one candidate
"If the Tea Party could get behind one person and call it a day," says Patricia Murphy at The Daily Beast, it could be a force in the presidential election. But the conservative politicians that small-government, anti-tax activists truly love — Sens. Jim DeMint (R-S.C.) and Rand Paul (R-Ky.), for example — aren't running. Instead, Tea Partiers must choose from a field of candidates that all have "original sins against constitutional freedom or fiscal sanity." Tea Partiers aren't excited or in sync, and as a result, "for the Tea Party movement, the 2012 presidential primaries have been a bust."

2. And now they're reluctantly settling for Romney
"Not Romney" has been the favorite choice of Tea Party activists, Chris Littleton, co-founder of a Tea Party coalition called the Ohio Liberty Council, tells The Daily Beast. But after consecutive wins in Florida and Nevada, the former Massachusetts governor looks increasingly like the inevitable Republican nominee. So Romney has begun picking up an increasing share of the Tea Party vote, says Kristen Wyatt for the Associated Press. It seems many Tea Partiers are "reluctantly backing him after abandoning hope of finding a nominee they like better."

3. The Tea Party's influence was overstated in the first place
Maybe Tea Partiers never really were the backbone of the GOP base, says Gene Smith at the Fayetteville, N.C., Observer. Instead, they made up "a mere appendage (albeit a large one) that achieved a fleeting fame" while doing battle with former House Speaker Nancy Pelosi. Once they succeeded in "bullying a tremulous speaker," Tea Partiers simply went back to the sidelines.

4. Tea Party influence isn't waning — it has evolved
Tea Party rallies are so 2010. "People realize it is time to move beyond rallies and into other efforts," Jeff Crank, head of the Colorado chapter of the Tea Party-linked Americans for Prosperity, tells the Durango, Colo., Herald. While many activists have rolled up their "Don't tread on me" flags and gone home, the core of the movement still wields considerable influence through the 85 new Republican congressional representatives they helped elect in 2010. "On their own, the small, decentralized Tea Party groups have had a hard time getting involved in the presidential race," says Joe Hanel in the Herald. But they'll still make their presence known in local congressional races. They haven't disappeared; they've just "evolved."