WASHINGTON - With the end of the 2000 Census, the state-by-state fight over redistricting begins in earnest this month as  Republicans and Democrats start redrawing congressional boundaries that could seal their political fates for the next decade.

Relying on detailed, block-by-block census counts that start going to states this week, state lawmakers who control the redistricting process  could dramatically reshape the balance of power in the House of Representatives with the simple shift of a few district lines.

``The starter's pistol is about to go off,'' Tom Hofeller, redistricting director for the Republican National Committee (news - web sites), said of  the once-a-decade process to ensure each congressional district represents roughly the same number of people.

The subject of intense planning by national and state parties, congressional redistricting is the ultimate exercise in wielding political power,  shaping political futures and protecting political ambitions, analysts say.

In 44 of the 50 states, the process begins in the state legislature, giving the party in control first crack at drawing a map to their political  advantage.

Both parties claim to be in good shape as the process begins. Republicans expect to pick up seats and Democrats are optimistic they can  stay even as the two parties hold almost equal power in state legislatures.

``I really do think it's fairly even,'' said Tim Storey, an analyst at the National Conference of State Legislatures. ``But the Republicans are  considerably better off than they were 10 years ago, and they've done pretty well in the last 10 years.''

Retirements Likely

A variety of factors could affect the outcome, however, including the trend toward more retirements in redistricting years, the onset of term  limits on many state legislators and the likelihood of court battles over the final product.

``It's like one of those three-level chess games,'' Storey said. ``The number of elements are innumerable and unpredictable.''

The toughest fights are likely to occur in the 18 states that either lose or gain congressional seats as a result of the census figures.

Florida, Texas, Arizona and Georgia will gain two congressional seats each, while California, Colorado, Nevada and North Carolina each  gain one. New York and Pennsylvania each lose two seats, while Michigan, Ohio, Illinois, Wisconsin, Connecticut, Indiana, Mississippi and  Oklahoma each lose one.

``It's going to be pretty messy everywhere, but it's going to be particularly bloody in states where one party has control,'' said Robert Richie,  executive director of the nonpartisan Center for Voting and Democracy.

Democrats expect to take a hit in Pennsylvania, Michigan and Ohio, where Republicans control the process, and could face problems in  Florida and Texas. But they hope their control in Georgia, which gains two seats, and their dominance in California will help make up for the  losses.

``Pennsylvania, Michigan and Ohio are tough states for us but there are opportunities elsewhere,'' said Rep. Ken Bentsen (news - bio -  voting record), a Texas Democrat and co-chairman of the party's national redistricting effort. ``At the end of the day, our worst-case scenario  is a wash.''

Democrats Hope: Stay Even

Bentsen admitted, however, that under the most optimist Democratic scenarios they would do only slightly better than stay even. ``The  deviation from best-case to worst-case scenario is rather narrow,'' he said.

Hofeller said Republicans were in much better shape than 10 years ago, when Democrats largely controlled the redistricting process. ``I'm  very comfortable with the way most key states are lined up for us,'' he said.

Lawmakers in states losing congressional seats could be forced to pit incumbents against one another, a prospect that has had many  nervous members of Congress lobbying their home legislators feverishly.

Connecticut could see a matchup between Democrat James Maloney and Republican Nancy Johnson; in Mississippi, Democrat Ronnie  Shows and Republican Charles Pickering might be forced into a head-to-head battle. Indiana might have been spared a traumatic  showdown of veterans with the recent retirement of Democrat Tim Roemer.

The prospect of such matchups -- after the 1990 census, 20 incumbents were forced to run against each other -- is often enough to  convince congressional veterans that it is a good time to retire or seek other office.

There were 40 retirements in 1982 and 65 in 1992, the first elections after redistricting. Already this year, seven House members have  announced they will retire or seek higher office.

Complicating the picture is the term limit requirements placed on state legislators in 19 states, which have many local heavyweights  contemplating a race for Congress in the next election, Storey said.

And an eventual court challenge of each state's redistricting plan is almost a given. In 1990, 41 states wound up in court over their  redistricting plans.

Another 16 states require Justice Department (news - web sites) approval of their redistricting plans to ensure they are in keeping with the  Voting Rights Act, Storey said.