Nikki Haley speaks to supporters after winning the Republican nomination for governor Tuesday in Columbia, S.C.

Los Angeles ? With the election season more than halfway over, the “tea party” movement has notched some impressive victories but also learned a hard lesson: There are limits to the power of its anger-fueled insurgency.

The movement scored a big win last week in South Carolina, where state Rep. Nikki Haley romped past a four-term congressman to win the GOP nomination for governor. Still, for all the attention the tea party has gotten and all the passion of its followers, a rough accounting at the ballot box shows the movement has just about as many losses as victories.

Money has proved an impediment. Organization — or, rather, the lack of it — has become another.

“Just being a tea party candidate or being an outsider is not enough,” said Nathan Gonzales, who tracks elections nationwide for the nonpartisan Rothenberg Political Report. “You have to have money to establish a level of credibility in order to win. You have to have an organization and a focus to have an effect.”

The two candidates who have arguably done the most to raise the party banner, Senate candidates Rand Paul in Kentucky and Sharron Angle in Nevada, were both well funded: Paul through supporters of his father, former Republican presidential hopeful Ron Paul, and Angle through a hefty cash infusion from the anti-tax group Club for Growth.

Most tea party candidates have been less fortunate. In the California primary for U.S. Senate, GOP Assemblyman Chuck DeVore of Irvine was a favorite of the movement, but fell to the millions spent by wealthy businesswoman Carly Fiorina, a more mainstream Republican.

Strategists say merely tallying election results fails to reflect the tea party’s true significance. The movement — loud, aggressive, diffuse — has been a powerful force in the age of Barack Obama, rallying opposition to the president and his expansive agenda, dogging congressional Democrats and purging Republicans deemed insufficiently faithful to the creed of lower taxes and smaller government.

“You can measure it by the fact that almost every candidate, Democrat or Republican, sounds like they belong to the tea party movement,” said Sal Russo, impresario of the Tea Party Express, one of the most visible of the groups bearing the name. “You don’t find anybody out there saying, ‘Let’s spend a whole bunch of money and we don’t have to worry about our deficit and adding to the debt.'”

Still, the tea party — born in an anti-Washington fever about 14 months ago — has yet to prove its long-term viability, or whether followers can accomplish more than raising a sizable ruckus. The key test will come in November, when movement-backed candidates test their appeal outside the friendly confines of a GOP primary, courting disaffected Democrats and, more importantly, independent voters.

Won some, lost some

In addition to Nevada, Kentucky and South Carolina, the tea party has prevailed in Utah and Florida, where Republican Sen. Robert F. Bennett lost re-election and Charlie Crist was chased from the GOP for ideological impurity; Massachusetts and Maine, where Sen. Scott Brown and gubernatorial hopeful Paul LePage surged thanks to movement support; and Georgia, where the party helped send an ally to Congress in a special election.

The losses, besides California, include races in Texas, Indiana, New York, New Jersey, Pennsylvania and Virginia. In part, that reflects the splintered nature of the movement.

The tea party is proudly, militantly bottom-up. There are hundreds of chapters, with no centralized leadership and any number of factions claiming to be the true keeper of the faith.

That is terrific for grass-roots democracy. But the practical effects can be vexing, as shown in Indiana and Virginia, where the lack of consensus divided the tea party vote and handed victory to candidates of the hated establishment.

“My biggest regret so far is when we fail to circle the wagons around the right candidate,” said Matt Kibbe, the president of FreedomWorks, a conservative advocacy group and strong tea party ally.

Tensions between tea party members and Republican regulars are likely to melt away once fall arrives, allowing them to direct their ire at a common foe: the Democrats running Congress. The question is whether restive Democrats and independents, who hold the balance of power in the midterm vote, come along in sufficient number to elect unorthodox candidates like Paul and Angle and tea party favorites like LePage and Marco Rubio in Florida.

Then the party could prove its durability, and become a force in the 2012 presidential campaign.