Three and a half weeks to go until Election Day and it isn’t certain that even a half-dozen open seats in the House will change party control.

[IMGCAP(1)]The small number of open seats that might go the other way in November continues to limit the number of House seats that Democrats can hope to net next month. At least this time, I found a dozen potentials, unlike my June installment, which only included 10.

Here are the current open seats most likely to switch party, with the first ones significantly more likely to switch than those at the end of the list. (I’ve excluded Texas’ districts since redistricting makes comparisons difficult.)

Colorado’s 3rd. While this district favors a generic Republican, the Democrats have a strong candidate in state Rep. John Salazar, brother of Colorado Attorney General (and Democratic Senate nominee) Ken Salazar. A divisive primary produced former state Department of Natural Resources head Greg Walcher as the Republican nominee. Polls show that the race is tight, but the GOP could easily let this one slip away.

Kentucky’s 4th. This district should be an obvious GOP pickup given voters’ partisan preferences, but Republicans — and nominee Geoff Davis — still haven’t pegged Democrat Nick Clooney as too liberal for the district. The GOP is getting ready to unload on Clooney, and that, plus the district’s basic Republicanism, could still deliver this district to the party. But it’s no longer a foregone conclusion that the Republicans will recapture this seat.

New York’s 27th. Rep. Jack Quinn’s (R) retirement gives Democrats an excellent shot at a pickup, given the nature of the district. The Republicans have rallied around Erie County Comptroller Nancy Naples, while the Democrats chose state Assemblyman Brian Higgins. Naples is the stronger candidate, but the Democratic-leaning district clearly favors Higgins. Polling has the race even.

Louisiana’s 3rd. Retiring Rep. Billy Tauzin (R) hopes to pass along his House seat to his son, Billy Tauzin III (R). But state Sen. Craig Romero (R) has money and a base. Three credible Democrats — former state Rep. Charlie Melancon, who is a former president of the American Sugar Cane League, Charmaine Caccioppi, an aide to then-Sen. J. Bennett Johnston (D), and state Rep. Damon Baldone — are also in the race, which is expected to go to a runoff. The younger Tauzin has name ID but may not be ready for prime time. Even worse, he looks like a Capitol Hill intern. This seat is clearly a problem for the Republicans.

Washington’s 8th. The retirement of Rep. Jennifer Dunn (R) creates a GOP headache in this swing district, which went narrowly for Al Gore in 2000. The Democrats nominated talk show host Dave Ross, while the Republicans selected King County Sheriff Dave Reichert. Polls are contradictory. The race could go either way.

Louisiana’s 7th. Republicans have a shot to capture Senate hopeful Rep. Chris John’s (D) seat, and party insiders have rallied behind heart surgeon Charles Boustany. Two Democrats are battling it out for an expected spot in a runoff. The district favors conservative Democrats.

Pennsylvania’s 8th. Rep. Jim Greenwood’s (R) late retirement gives Democrats the first of three opportunities in the Keystone State. But Ginny Schrader (D) starts behind Bucks County Commissioner Mike Fitzpatrick (R) in the GOP-leaning, suburban Philadelphia district. Democrats hope that abortion becomes the key issue, with Schrader, a strong abortion rights advocate, and her opponent, who is anti-abortion rights. A Democratic long shot.

Nebraska’s 1st. Democrats know the numbers favor the GOP, but they think the winner of a divisive three-way Republican primary, conservative activist Jeff Fortenberry, is just the kind of candidate they can beat. State Sen. Matt Connealy (D) hopes to pull off an upset in a district left open by retiring Rep. Doug Bereuter (R), but Fortenberry has the edge.

Washington’s 5th. Democratic businessman Don Barbieri has the financial resources he needs to run a quality campaign, but the district gave George W. Bush 57 percent in 2000 and Eastern Washington is conservative territory. State Rep. Cathy McMorris won the GOP nomination, and she is a good candidate. The Democrats have talked this race up, but realistically they’ll need some luck to pick this one off.

Pennsylvania’s 15th. Democratic strategists continue to push businessman Joe Driscoll’s candidacy, but that still looks like wishful thinking on their part. Driscoll is struggling to overcome the carpetbagger label, while state Sen. Charlie Dent (R) is a proven vote-getter. Yes, the district is inherently competitive, and a national Democratic wave could help Driscoll. But Dent has a solid lead in polling.

Pennsylvania’s 13th. State Sen. Allyson Schwartz (D) is favored to hold this seat for the Democrats now that Rep. Joe Hoeffel is running for the Senate. While the district, which includes parts of Philadelphia and suburban Montgomery County, leans Democratic, GOP nominee Melissa Brown almost upset Hoeffel two years ago. Schwartz used her name ID and financial edge to win the Democratic nomination, but Brown is a credible opponent.

California’s 20th. The National Republican Congressional Committee is putting money behind state Sen. Roy Ashburn, but former state Sen. Jim Costa (D) is the clear favorite to hold retiring Democratic Rep. Cal Dooley’s open seat.

Stuart Rothenberg is editor of the Rothenberg Political Report .