In an Alaska political shocker, Lt. Gov. Sean Parnell announced Friday before a crowd at the Republican Party convention that he is challenging embattled U.S. Rep. Don Young in the August Republican primary.

"I just think it's about restoring trust to government," Parnell said.

Young, attending the convention, had a quick response: Bring it on.

Young, who has won 18 times as Alaska's lone congressman, says his seniority is what counts.

"A 35-year head start," Parnell called it.

Parnell immediately got the backing of Gov. Sarah Palin, whose husband, parents and siblings were part of a cheering group gathered outside of the state Division of Elections for Parnell's news conference on entering the race.

"This race is not going to be about Don Young, in my mind," Parnell told reporters. "It's going to be about what we can do for Alaska. I'm just willing to step forward, be that new energy for Alaska and be accountable for what we're doing in our public lives." He was flanked by his wife, Sandy, and Palin.

Parnell's news surprised party leaders and just about everyone else attending the GOP convention at the Hotel Captain Cook, said Republican Party chairman Randy Ruedrich, who is fighting his own battle over his leadership of the fractured party.

"He's a great guy. He's articulate," Ruedrich said. "I've known him a long time. He'll be a relevant candidate. Now it's all a matter of building a campaign organization, getting your message out."

When some people stood up to cheer Parnell's news, "one of those was Congressman Young," said former Lt. Gov. Loren Leman, who also had been considering a run at Young's seat. "But he was doing it, what do you call it, tongue in cheek."

"Sean, congratulations," Young told the convention. "I beat your dad, and I'm going to beat you."

In the 1980 general election, Young easily beat Pat Parnell, who ran as a Democrat. Young got 70 percent of the vote that year.

As to the younger Parnell, Young later told Alaska Public Radio Network: "He's all right. I'm a little disappointed he didn't tell me. I thought that showed a little lack of class."

Parnell's announcement followed Palin's convention speech. She called for changes atop the party but stopped short of mentioning her nemesis, Ruedrich.

"I think we need to call on all of you assembled delegates to rise and, literally even, stand with me if you desire change in our party's leadership," Palin said, and about half of the crowd in the ballroom did, to sustained applause and cheering.

So far, party leaders have blocked efforts to oust Ruedrich before his term ends in 2010.

Young, 74, has been under intensive scrutiny for months. According to various media reports, he's under investigation for his ties to Veco Corp., for fundraising activities and for his role in specific congressional earmarks that may have benefited financial backers.

Young has supported convicted lobbyist Jack Abramoff on a number of issues, including blocking legislation granting federal protection to workers on the Mariana Islands, a U.S. territory. One of Young's aides on the transportation committee, former Alaskan Mark Zachares, pleaded guilty in April to conspiring to provide Abramoff inside government information in return for cash, gifts and a job.

Young has not been charged with any wrongdoing, but his re-election campaign spent $854,035 on legal fees during 2007. He has since established a separate fund for his own legal defense.

Palin alluded to Young's big legal bills on Friday, saying Parnell "won't be spending his campaign funds on attorneys. That's an assurance."

Parnell, 45, said that he hadn't spoken with national party leaders about taking on Young but that dozens of Alaskans urged him to do so. Over the last week, he and his wife of 20 years, Sandy, decided he should go for it, he said. The couple have two teenage daughters who attend Grace Christian School. He was an Anchorage attorney at Patton Boggs before his election as lieutenant government. He served two state House terms and one Senate term before leaving office in 2001.

Young's attitude at a rare news conference in February factored into the decision, Parnell said. Video of that news conference in Anchorage got lots of attention on various media Web sites. In the news conference, Young refused to explain his legal bills or to answer questions about the investigation and contended his constituents weren't interested in that. He said Alaskans who didn't vote for him weren't his constituents.

"Certainly the last interview played a part where he indicated that because somebody didn't vote for him that they were not his constituent. That is wrong in my estimation," Parnell said. "Part of the public trust is even if somebody doesn't vote for us we represent them in the best way that we know how. That was something that got me talking a lot more about it."

It's a crowded field. Besides Parnell, state Rep. Gabrielle LeDoux, R-Kodiak, also is running in the Republican primary. LeDoux said she heard rumors over the past week that Parnell might jump in, but she'll stay in the race and travel the state for votes.

"When I originally got into the race, I was expecting all sorts of people to be getting into it so it doesn't surprise me that Sean got into it and it's not going to surprise me if a couple more people get into it," she said.

The winner of that contest will face whoever comes out on top among the Democrats, who now include former state Rep. Ethan Berkowitz, former state party chairman Jake Metcalfe and writer Diane Benson.

"It's clear the people of Alaska are hungry for change and Republicans are offering more of the same failed Bush policies," said Doug Thornell, a spokesman for the Democratic Congressional Campaign Committee. "We are high on this seat and believe we can win regardless of who ends up winning the GOP nomination."

Young left no doubt that he's running hard.

"This campaign will be about who can represent Alaska's interest in Congress against the anti-Alaska Democratic leadership that would rather see Alaska gated and turned into a National Park," he said in a written statement.

Parnell said he intends to remain lieutenant governor while campaigning. If he wins, Attorney General Talis Colberg will become lieutenant governor, under a line of succession that Palin announced soon after becoming governor, her aides said.

Find Lisa Demer online at adn.com/contact/ldemer or call 257-4390. Daily News reporter Erika Bolstad, The Associated Press and Alaska Public Radio Network contributed to this story.