WASHINGTON -- The Republican-drawn congressional map approved Friday by the Texas House delivers a brisk one-two punch: It targets a number of conservative and moderate Democrats in Congress and jeopardizes the re-election of vigorous GOP opponents Lloyd Doggett and Martin Frost.

By placing at risk up to 10 sitting Democrats, the Republican mapmakers can accomplish far more than merely boost their party's majority in a closely divided Congress.

The GOP can move the entire Democratic Party toward the left, solidify Republican standing among rural voters and dismiss a number of Democrats they have tried for years to defeat, political observers said.

The new map increases the number of solidly Republican and solidly Democratic districts, continuing a national trend that took off in the 1980 round of redistricting. GOP candidates in these safe districts typically face challengers from the right ó or the left if they're Democrats ó so there is little incentive to seek out moderate, independent and opposition-party voters.

"There may very well be a day in the not-too-distant future where we have a Congress where all conservatives are Republicans and all liberals are Democrats," said Jim Riddlesperger Jr., political science department chairman at Texas Christian University.

"It's the case of the vanishing moderate," said Amy Walter, who analyzes the U.S. House for the Cook Political Report. "And when those voices go away, they are usually replaced by a very partisan member."

Four of the targeted Texas Democrats are members of the Blue Dog Coalition, party conservatives and moderates who focus on a balanced budget while attempting to steer Democrats on a more centrist policy course.

"They've got us targeted because we're an independent voice, and we're the very types of representatives that drive (House Republican leader and fellow Texan) Tom DeLay crazy. We don't blindly follow party policy on either side," said U.S. Rep. Max Sandlin, a Blue Dog from Northeast Texas. "They don't want districts that are competitive, or that they can win. They want districts that they absolutely can't lose."

All four Blue Dogs, including U.S. Reps. Ralph Hall of Rockwall, Charlie Stenholm of Abilene and Jim Turner of Crockett, represent districts that have grown increasingly Republican as the GOP has gained dominance in Texas. They have survived by reflecting their districts' conservative values.

Sandlin favors a constitutional amendment banning desecration of the U.S. flag. Hall voted for President Bush-backed bills 70 percent of the time in 2002. Stenholm opposes abortion.

Other targeted Democrats also contribute to their party's diversity of opinion. Rep. Gene Green, D-Houston, opposes gun control and favors the death penalty. Rep. Chet Edwards, D-Waco, follows a pro-military and pro-business agenda.

"That's part of the reason that they are being targeted," Riddlesperger said. "Republicans want to lay claim to conservatism in the United States. They would rather not have to rely on conservative Democrats in order to do that.

"It's something some observers of political parties have wanted for years ó to have what we would call responsible parties, where you can tell something about a congressman based on what party he belongs to," he said.

Republicans say they had two goals when redrawing congressional districts: to elect more Republicans and to improve opportunities for minority voters to elect candidates of their choice.

The 10 targeted Democrats, all white men, were included in districts that traditionally back Republican candidates or, as in Hall's case, were put into new districts where they lose the incumbent's advantage of name recognition and fund raising.

While the parties disagree ó strongly ó on whether minority voters are helped by the new map, the redrawn districts concentrate Democratic strength in districts dominated by black and Hispanic voters. "I would suspect that (any Democrat) who is not in a minority district would have a very competitive race," Republican state Rep. Phil King, the House's chief mapmaker, said recently.

Doggett, an Austin Democrat, complained that the strategy is an attempt to marginalize his party.

"The Republicans have traditionally had a subtle message in many campaigns that Democrats are only interested in minorities. Now they carry that to next level: Only minorities represent and speak for all Democrats," he said.

Most targeted Democrats won't have the flexibility of Green, the Houston Democrat who vowed to move from the heavily Republican district that was recently drawn for him. Green said he will relocate to a nearby district that contains many of his current voters, has no incumbent and a high concentration of Hispanic voters.

"I will probably be the only Anglo in the Democratic delegation," said Green, who has defeated Hispanic primary challengers in the past.

Walter, the congressional observer, said Democrats also stand to lose their few remaining members tied to rural communities, such as Stenholm, a cotton farmer, and Hall, who is 80 and who said he will study his new district before deciding whether to seek a 13th term.

"They are speaking up for a part of the country that, at one point, was dominated by Democrats but now is dominated by Republicans," Walter said. "Those other voices are helpful in bringing a sort of diversity to the party's legislative focus ó and to the understanding of how things look in other parts of the country. The way you talk about guns in suburban Philadelphia is not how you talk about guns in San Angelo."

The influence of rural Democrats was felt in the 2002 election, when the Democratic Party soft-pedaled the hot-button issues of gun control and abortion, she said.

"After the 2000 election, a lot of rural Democrats came to the Democratic leadership and said, 'You can't talk about guns; it's killing us,' " Walter said. "That's something they brought to the table."