The Tea Party movement has many more incumbent Republicans in its sights this midterm election year after tossing out an incumbent conservative GOP senator in Utah.
In its first real show of political force, the Tea Party movement unseated three-term Sen. Bob Bennett in the state's Republican primary race Saturday.
"It's the beginning of a trend," journalist Robin Wright said Sunday on ABC News' "This Week."
Bennett's loss to two Tea Party candidates, former assistant U.S. Attorney Mike Lee and businessman Tim Bridgewater, sends a warning signal to other GOP incumbents in a year when an anti-Washington, pro-fiscally conservative current is running strong among Republicans.
"You have the next coming up, Kentucky and Arizona and New Hampshire. We're likely to see this elsewhere," Wright said. "Democracy's about the majority, but it's about the majority of people who participate. And, in this case, a certain kind of people participated, and their candidate won."
The Tea Party's next big political fight will take place May 18 in Kentucky's Republican Senate primary. Although Secretary of State Trey Grayson has the support of the Senate Minority Leader Mitch McConnell and other Republican state establishment, he is running against Tea Party favorite Rand Paul, the son of former presidential candidate Ron Paul of Texas. Paul is also supported by Sarah Palin and evangelical leader James Dobson.
Although Bennett blamed the "toxic" political environment, even he conceded that his Senate votes may have been a problem. His votes for health care overhaul and the Trouble Asset Relief Program, painted by critics as the "Wall Street bailout," enraged members of the Tea Party movement, who hope to purge incumbents of questionable conservative purity.
"The political atmosphere obviously has been toxic and it's very clear that some of the votes that I have cast have added to the toxic environment," Bennett said Saturday in his concession speech.
Although their support for the GOP-backed fiscal conservative Marco Rubio may have caused Florida Republican Gov. Charlie Crist to run as an independent in the upcoming senate race there, Utah was Tea Party supporters' first breakthrough victory.
John Avlon, co-author of "Wingnuts: How the Lunatic Fringe Is Hijacking America," said on ABC, "This is a marker in the evolution of the Tea Party movement into becoming a real political force."
Tea Party: Not Just 'Astroturf'?
"They have succeeded in taking out a Republican senator who is by most accounts a fellow conservative because he was insufficiently conservative when it came to government spending. That is a real marker of a movement that is reaching maturity," Avlon said.
In a competitive year when only 56 percent of Republicans say their party best represents their values, moderate Republican incumbents are targets.
According to a recent ABC News poll, 56 percent of Republicans say their party best represents their values, and 30 percent of Republicans say they pick the Tea Party movement instead of the GOP. This contrasts with the Democratic Party, where 86 percent of Democrats say their party best represents their values.
Still, others chalk it up to anti-Washington sentiment and not necessarily pro-conservatism.
"This is an anti-Washington year," conservative columnist and ABC News contributor George Will said. "How do you get more Washington than a three-term senator who occupies the seat once held by his father, a four-term senator, who before that worked on the Senate staff and then as a lobbyist in Washington? He's a wonderful man and a terrific senator, but the fact is, he's going against terrific headwinds this year, and he cast three votes, TARP, stimulus, and an individual mandate for health care.
"Now, you might like one, two or all three of those, but being opposed to them is not outside the mainstream of American political argument."
Author Avlon said, "If they stay on fiscal issues, they can have a real impact on this election. There's no question. They have been able to channel voter anger into something that is genuinely grass roots not Astroturf."
There have been predictions for months that the Democrats will take a big hit in the midterm election, but the ouster of Bennett shows that incumbents in both parties should be worried.
"Just because you have an 'R' next to your name doesn't mean you're safe this year," said Ramesh Ponnuru, a senior editor for National Review magazine.
But even with a Utah victory, and Palin's support, the Tea Party movement still faces significant challenges. A recent ABC News/Washington poll published May 5 showed that of the 27 percent who support the Tea Party movement, only 17 percent "strongly" support it, and only 2 percent say they're "active participants."
"They are going to need to show if they can actually beat Democratic incumbents and actually beat Republican incumbents -- and sort of put the fear of God into the party a little bit -- and that the activist base is a force to be reckoned with, not just to be used to advance the party's chosen candidates," Politico's Alexander Burns told ABC.
ABC News' David Kerley contributed to this story.