Some of Virginia's senior lawmakers have announced their retirements, and more may follow, leaving behind a state legislature already brimming with young, inexperienced politicians who are learning on the job.

Three of the 10 longest-serving members of the House of Delegates and two senior senators are leaving. Two are Republicans, who hold the majority in both chambers, and three are Democrats, whose party lost its century-long grip on power three years ago.

The remaining lawmakers say the loss of institutional memory and legislative skill will be a severe blow to a state struggling to address such complicated issues as tax restructuring and spending on education and transportation.

"It's an entire new generation, there's no question about that," said veteran Del. Vincent F. Callahan Jr. (R-Fairfax), who has served in the House since 1968 and is running for reelection. "Many of them could be my children."

Some say the departures will accelerate a trend in both houses away from moderate, middle-of-the-road lawmaking in favor of brash, fringe politics.

Sen. Richard L. Saslaw (D-Fairfax), who has served more than 30 years in the legislature, said he believes lawmakers move to the political center as they gain experience. When longtime lawmakers leave, he said, often they are replaced with more polarizing members.

"The reality of life is very sobering," Saslaw said. "Generally, first-term people tend to come in as firebrands and get nothing done."

The statistics about both chambers are striking for a state that does not impose term limits. One out of every four House members has served one two-year term, and 60 percent of the 100 members have been in office fewer than 10 years. More than a third came to Richmond after 2000.

Two veteran Northern Virginia lawmakers, Dels. L. Karen Darner and James F. Almand, both of Arlington, have said they will not run again. So have two delegates from the Roanoke area, A. Victor Thomas and Clifton A. "Chip" Woodrum. All are Democrats.

Colleagues say several others are considering whether to quit.

In the Senate, eight of the 40 senators were elected before 1992, the last time Virginia was struggling to emerge from a recession. One of them, Sen. Kevin G. Miller (R-Harrisonburg), is not running for office again. Sen. Malfourd W. Trumbo (R-Botetourt) also has announced his pending retirement.

The longest-serving senator, Charles J. Colgan (D-Prince William), has not said whether he wants an eighth four-year term.

"I'll be 81 at the end of another term, so that's one of the things I'm looking at," he said.

Colgan, who said he would decide his political future within a week, said he worries about the impact of so many inexperienced lawmakers. He said the quality of the laws being passed might suffer.

"That much inexperience can be a problem," Colgan said. "It's an opportunity for lobbyists to convince the younger guys and the younger gals, where the older guys know better. The younger people depend more on the staff."

Longtime observers of politics in Richmond say the loss of experience in the General Assembly is cyclical, often coming every 10 years after the legislature redraws the boundaries of political districts -- to the benefit of some incumbents and the detriment of others. In 1972, for example, large numbers of new delegates and senators were elected.

And a lack of experience might not be all bad, they argue. Speaker William J. Howell (R-Stafford), who has served for 16 years in the House, said he counts on the new, younger members in his party as much as the older, more experienced ones. "It's exciting," he said. "These new people bring a lot of excitement and enthusiasm. They are not jaded yet."

Freshman Del. J. Chapman Petersen (D) said he agrees. A former Fairfax City Council member, Petersen said he is more in touch with his district and more willing to be open to new ideas than many of his colleagues with years of experience.

"You come in, you are right out of your district, you have a fresh perspective, a perspective that's much more immediate," Petersen said.

Robert D. Holsworth, who directs the Center for Public Policy at Virginia Commonwealth University in Richmond, said there are tradeoffs when legislatures churn quickly: Energetic new members offer fresh ideas but lack historical perspective.

"There's a general feeling that if you have less institutional knowledge, the attention to nuance, the understanding of the big picture is more difficult to possess," he said. "What you tend to get with the newer people is a little bit more aggressive agenda, a certain degree of boldness. Politics can always use that kind of infusion."

Others say they worry about what they see as less experience than in prior generations. Del. Brian J. Moran (Alexandria) was elected in 1996. Eight years later, he is poised to become more senior than half the other delegates, and he serves as his party's caucus chairman.

"When I got here, eight years was considered a junior member," Moran said. "Now, I'm a senior member on the Democratic side."

Moran said many of his Democratic colleagues, some of whom have been in the House for decades, have been forced into unfriendly new districts. Others have less interest in staying on when they have little influence on the agenda's direction or the legislation's outcome.

There are 64 Republicans in the House and 34 Democrats. Two delegates are independents.

"There's a lot of people in there that are good candidates. They run good campaigns," Moran said. "But in terms of policy and thought-provoking methods to address problems, there's not a lot of it. It may be because they are green, and they are thinking of campaigning instead of governing."