WASHINGTON - Is the tea party the new Republican Party?

The grass-roots network of fed-up conservative-libertarian voters displayed its power in its biggest triumph of the election year: the toppling of Sen. Lisa Murkowski in Alaska's GOP primary. Political novice Joe Miller is the fifth tea party insurgent to win a GOP Senate nominating contest, an upset that few, if any, saw coming.

With the stunning outcome, the fledgling tea party coalition and voters who identify with its anti-tax, anti-spending sentiments proved that democracy is alive and well - within the Republican Party. Don't like who is representing you? Rise up, fire them and choose someone new.

The tea party has taken hold in the Grand Old Party, unseating lawmakers, capturing nominations for open seats and forcing Republicans to recalibrate both their campaign strategy and issues agenda. Out is talk of delivering federal dollars back home; in is talk of fiscal discipline.

Within minutes of Murkowski conceding late Tuesday night, Sen. Jim DeMint, R-S.C., was among the conservative Republicans cheering Miller.

"He pulled off the upset victory of the year because he ran on principles and because Alaskans, like all Americans, want to stop the massive spending, bailouts and debt that are bankrupting our country," said DeMint.

Taking a shot at Murkowski if not the entire Republican establishment, he added: "Joe Miller's victory should be a wake-up call to politicians who go to Washington to bring home the bacon. Voters are saying 'We're not willing to bankrupt the country to benefit ourselves.'"

Murkowski, who was seeking her second full term, was the first GOP incumbent to lose her renomination bid to a tea party-backed challenger in a Republican primary.

But Utah Sen. Bob Bennett lost his job, too, fired at the state convention in May when tea party activists and other GOP voters rallied behind Mike Lee. And tea party favorites Rand Paul in Kentucky, Sharron Angle in Nevada and Ken Buck in Colorado won their primaries over establishment-supported candidates in open races.

Now, the country's latest political phenomenon is turning its sights on the Sept. 14 Delaware Senate primary in hopes that its preferred candidate can vanquish a moderate hand-picked by GOP leaders in Washington, Rep. Mike Castle, to win an open seat once held by Vice President Joe Biden.

"Up next: Christine O'Donnell for U.S. Senate in Delaware," declared Amy Kremer, chairman of the Tea Party Express, which says it spent some $600,000 in the final weeks of Alaska's Senate race to help Miller. The California-based group says it will shell out $250,000 on O'Donnell's behalf.

Afterward, the coalition's challenge will be to prove that its might is more than a fluke by ensuring that tea-party GOP nominees beat Democrats on Nov. 2.

That won't be difficult in some places.

It's nearly a foregone conclusion that Miller, an attorney endorsed by friends Sarah and Todd Palin, will be a senator; Alaska is a Republican-leaning state in a clearly GOP year. Still, Senate Democrats moved quickly to see whether Miller's victory could give them an opening, conducting a poll to gauge the potential competitiveness of the race.