WASHINGTON - The defeat of incumbent Sen. Lisa Murkowski in Alaska's Republican primary is another notch in the belt for the Sacramento Tea Party Express, a project of Republican consultant Sal Russo.
The group is behind a string of major Republican primary surprises this year - including the nomination of Sharron Angle in Nevada and Mike Lee in Utah, who beat incumbent Sen. Bob Bennett.
No other group has so been so ambitious in targeting high-profile races and pulling off primary victories.
Tea Party Express' success has come the old-fashioned way: with hundreds of thousands of dollars in political attack ads. That strategy has made it a divisive player within a movement that some believe should represent a new people-powered politics. But it has also made Tea Party Express a considerable opponent for establishment politicians.
Tea Party Express spent $600,000 - more than half of that in the last week - on an advertising blitz that salvaged the cash-strapped campaign of insurgent Joe Miller. Murkowski was blindsided. She conceded defeat Tuesday in a narrow contest decided by a late count of absentee ballots.
"The fact that it was the tea party is not necessarily so significant, as much as half a million spent by anyone is significant," said Ivan Moore, an independent pollster based in Anchorage. "Based on population, it's like spending $10 million in California."
The group has now set its sights on another seemingly safe establishment Republican, nine-term Congressman and former Delaware Gov. Mike Castle. Seen as a shoe-in to take Vice President Joe Biden's former Senate seat, Castle is now under attack by Tea Party Express and conservative challenger Christine O'Donnell.
Tea Party Express plans to spend at least $200,000 on ads in the state, said Amy Kremer, chairwoman of Tea Party Express.
That sort of airwave warfare is among the reasons Tea Party Express has emerged as one of the more divisive players in the tea party universe. While other groups in the movement boast of their grassroots organizing and outsider status, Tea Party Express focuses on attention-grabbing bus tours that draw big crowds, big time speakers - such as Sarah Palin - and big fundraising hauls.
It then spends much of that money on traditional attack advertising - an expenditure that yields profits for a bevy of media buyers and consultants. Of the $5.2 million spent by Tea Party Express this election cycle, nearly $600,000 has gone through Russo's consulting firm, Russo, March and Associates, although some of that money was used to pay for vendors, transportation and other expenses.
It's that sort of spending that draws fire from other groups.
"Folks were not rallying on the National Mall to make media buyers in Sacramento, Los Angeles and San Diego wealthier," said Matt Robbins, national executive director of American Majority, a group that focuses on political training for tea party activists. "This is definitely business as usual. It's not the organic grassroots movement you've seen across the country."