Bushites, far right, uptight.

WASHINGTON " A rush of Republican retirements has positioned Democrats to pick up 20 or more seats in the House and transform what might otherwise be a march to modest gains on Election Day into a wave to a lopsided majority.

Across the country, GOP departures " many in districts the party has controlled for decades " have made an extraordinarily grim election year even tougher for Republicans.

If Democrats can capture a substantial number of the GOP's 29 so-called open seats, they will have a stronger hand in the new Congress at moving an agenda that includes raising taxes on the wealthy and cutting them for the middle class, steering more federal benefits to low-income families and expanding health care coverage.

They also might solidify what could be a long-lasting House majority by gaining footholds in areas that have been off-limits to Democrats for a decade or longer. Democrats now enjoy a 235-199 majority in the House, with one vacancy. While no one envisions them building that to a veto-proof 270-seat majority this election, the closer they approach it the better chances their agenda will have, even should Republican John McCain win the White House.

Richard Liebo of Bloomington, Minn., is the kind of voter they're looking to. Liebo, a self-described independent who doesn't much like what he calls the "far-right" drift of the GOP, over the past two decades has voted to return Republican Rep. Jim Ramstad to the House from Minnesota's 3rd District. He viewed his nine-term congressman as a "middle-of-the-roader" who worked "for everyone's benefit" in his suburban territory west of the Minneapolis-St. Paul.

But with Ramstad retiring, Liebo, 78, says this year is different. He's now leaning toward supporting the Democrat, Ashwin Madia, to succeed him.

"These open seats are the critical battleground," Ohio political scientist John C. Green said. They are, he added, "the difference between (Democrats) having a modest success and a great success."

Republicans are defending nearly five times the number of open seats than Democrats are protecting. These seats generally are considered much more vulnerable to takeover by the other party than those where incumbents are seeking re-election, because the candidates lack the powers of a sitting lawmaker, such as name recognition, money, and the kind of reputation and rapport with voters that Liebo described with Ramstad.

"It's where 75 percent of congressmen come from," said Ronald Keith Gaddie, a University of Oklahoma political scientist who has written a book on the trend. "There's only a 25 percent chance you bump off an incumbent," Gaddie said, so retirements and other departures are the ripest opportunities to flip seats from one party's column to another's.

This year two-thirds of the up-for-grabs GOP seats are at least somewhat competitive. Democrats hold solid advantages in six of them " in Arizona, Illinois, New York, Ohio and Virginia. Another 13 " in Alabama, California, Louisiana, Maryland, Ramstad's in Minnesota, Missouri, New Jersey, New York, New Mexico, Ohio and Wyoming " are toss-ups that could go either way on Election Day.

By contrast, just two of Democrats' six open seats are considered competitive, and only one of them, in Alabama, is considered a toss-up.

Democrats are dumping huge amounts of money and time into the up-for-grabs districts. They've poured $1.7 million " one of their biggest investments anywhere " into the open race to succeed retiring Rep. Rick Renzi, R-Ariz. Democrat Ann Kirkpatrick appears to have the advantage in the race over Republican Sydney Hay.

Elsewhere, from Ohio to New York, Democrats are leading GOP candidates in open contests.

Republicans, meanwhile, badly trailing Democrats in the race for campaign cash, have been hard-pressed to promote their candidates for open seats. The House GOP campaign arm isn't even spending in 10 of the most competitive open contests, instead devoting most of its money to defending vulnerable incumbents in an effort to limit losses on Election Day.