By Peggy Girshman, CQ Staff

When we at CQ Politics published our first race ratings for the 2008 congressional elections, it seemed likely that Democrats would pick up some House and Senate seats — expanding the majorities the party won with its big upsurge in the 2008 elections.

But only the most optimistic Democrat, or the most pessimistic Republican, would have predicted that the Senate and House races would break so expansively the Democrats’ way, or that such a vast majority of the changes CQ Politics has made to its ratings would reflect stronger opportunities for Democratic pickups.

The ratings — which run a spectrum from Safe Democrat to Democrat Favored to Leans Democratic to No Clear Favorite to Leans Republican to Republican Favored to Safe Republican — are regularly re-evaluated based on developments in the individual races and in national politics. And since November 2007, Democratic chances improved in 14 Senate races and 74 House races. For the Republicans, there’s not much to cheer about: their chances have improved in just two Senate and 8 House races.

There are multiple reasons behind these changes. The die was cast by a national political atmosphere which, much to the Republicans’ dismay, did not improve after 2006, as President Bush’s unpopularity and a sharp economic downturn weighed down the GOP. More than two dozen Republicans, sensing that they would spend another two years in the minority in the next Congress, chose to retire, while few Democrats did. That gloominess spread, as the Republican Party had difficulty recruiting top-tier candidates to defend their open seats or challenge Democratic incumbents, even some of those who on paper looked vulnerable.

The Democrats, meanwhile, have been much more successful at raising money for their congressional campaign committees than the GOP and those committees are sharing their bounty with their challengers and open-seat candidates running for seats currently held by Republicans. Scandals have changed the nature of a few races.

A note of caution: just because a rating moved more in favor of the Democratic candidate in a particular race, it doesn’t mean that the Democrat will necessarily win. Republican candidates are still favored, slightly or strongly, in many of the races in which the Democrats’ prospects have improved. But the Democrats’ ability to “spread the playing field” is forcing the Republicans to spend their resources more broadly, raising the possibility of more Democratic takeovers — and forcing the GOP to mostly play defense instead of staging strong raids to takeover Democratic-held seats.

The list below documents the race in which CQ Politics has changed its ratings.

CQ Politics Race Rating Changes Favoring Democrats

Senate Seats

Alaska: Ted Stevens , R

One year ago: Republican Favored

Six months ago: Leans Republican

Today: Leans Democratic

Colorado: Wayne Allard , R, retiring

One year ago: No Clear Favorite

Six months ago: No Clear Favorite

Today: Democrat Favored

Georgia: Saxby Chambliss , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: No Clear Favorite

Iowa: Tom Harkin , D

One year ago: Democratic Favored

Six months ago: Democratic Favored

Today: Safe Democratic

Kansas: Pat Roberts , R

One year ago: Safe Republican

Six months ago: Republican Favored

Today: Republican Favored

Kentucky: Mitch McConnell , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: Leans Republican

Mississippi Special Election: Roger Wicker , R (replaced Trent Lott , R, who resigned)

One year ago: Safe Republican

Six months ago: Republican Favored

Today: Leans Republican

Montana: Max Baucus , D

One year ago: Democratic Favored

Six months ago: Safe Democrat

Today: Safe Democratic

New Hampshire: John E. Sununu , R

One year ago: No Clear Favorite

Six months ago: No Clear Favorite

Today: Leans Democratic

New Mexico: Pete V. Domenici , R, retiring

One year ago: No Clear Favorite

Six months ago: Leans Democratic

Today: Democrat Favored

North Carolina: Elizabeth Dole , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: Leans Democratic

Oregon: Gordon Smith, R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: No Clear Favorite

South Dakota: Tim Johnson , D

One year ago: Democrat Favored

Six months ago: Safe Democratic

Today: Safe Democratic

Virginia: John Warner, R, retiring

One year ago: Democrat Favored

Six months ago: Democrat Favored

Today: Safe Democratic

House Races

Alabama 2: Terry Everett , R, retiring

One year ago: Safe Republican

Six months ago: Leans Republican

Today: No Clear Favorite

Alabama 3: Mike D. Rogers , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Alaska At-Large: Don Young , R

One year ago: Leans Republican

Six months ago: No Clear Favorite

Today: Leans Democratic

Arizona 1: Rick Renzi , R, retiring

One year ago: No Clear Favorite

Six months ago: Leans Democratic

Today: Leans Democratic

Arizona 3: John Shadegg , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: Leans Republican

California 3: Dan Lungren , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

California 4: John T. Doolittle , R, retiring

One year ago: Leans Republican

Six months ago: Leans Republican

Today: No Clear Favorite

California 26: David Dreier , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

California 46: Dana Rohrabacher , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

California 50: Brian P. Bilbray , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Colorado 4: Marilyn Musgrave , R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: Leans Democratic

Connecticut 2: Joe Courtney , D

One year ago: Leans Democratic

Six months ago: Leans Democratic

Today: Democrat Favored

Connecticut 4: Christopher Shays , R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: No Clear Favorite

Florida 8: Ric Keller , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: Leans Democratic

Florida 18: Ileana Ros-Lehtinen , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Florida 21: Lincoln Diaz-Balart , R

One year ago: Safe Republican

Six months ago: Republican Favored

Today: Leans Republican

Florida 24: Tom Feeney , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: Leans Democratic

Florida 25: Mario Diaz-Balart , R

One year ago: Safe Republican

Six months ago: Republican Favored

Today: Leans Republican

Georgia 12: John Barrow , D

One year ago: Leans Democratic

Six months ago: Leans Democrati

Today: Democrat Favored

Idaho 1: Bill Sali , R

One year ago: Republican Favored

Six months ago: Republican Favored

Today: No Clear Favorite

Illinois 8: Melissa Bean , D

One year ago: Leans Democratic

Six months ago: Leans Democratic

Today: Democrat Favored

Illinois 10: Mark Steven Kirk , R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: No Clear Favorite

Illinois 11: Jerry Weller , R, retiring

One year ago: No Clear Favorite

Six months ago: Democrat Favored

Today: Leans Democratic

Illinois 13: Judy Biggert , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Illinois 14: Bill Foster , D

One year ago: Leans Republican

Six months ago: Leans Democratic

Today: Democrat Favored

Indiana 2: Joe Donnelly , D

One year ago: Democrat Favored

Six months ago: Democrat Favored

Today: Safe Democratic

Indiana 3: Mark Souder , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Leans Republican

Indiana 7: Andre Carson, D

One year ago: Leans Democratic

Six months ago: Leans Democratic

Today: Safe Democratic

Indiana 8: Brad Ellsworth , D

One year ago: Democrat Favored

Six months ago: Democrat Favored

Today: Safe Democratic

Indiana 9: Baron P. Hill , D

One year ago: Leans Democratic

Six months ago: Leans Democratic

Today: Democrat Favored

Kentucky 2: Ron Lewis , R, retiring

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Leans Republican

Louisiana 1: Steve Scalise , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Louisiana 4: Jim McCrery , R, retiring

One year ago: Safe Republican

Six months ago: Leans Republican

Today: No Clear Favorite

Louisiana 6: Don Cazayoux , D

One year ago: Safe Republican

Six months ago: No Clear Favorite

Today: No Clear Favorite

Louisiana 7: Charles Boustany Jr. , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Maryland 1: Wayne T. Gilchrest , R, defeated in primary

One year ago: Safe Republican

Six months ago: Republican Favored

Today: No Clear Favorite

Massachusetts 5: Niki Tsongas , D

One year ago: Leans Democratic

Six months ago: Democrat Favored

Today: Safe Democratic

Michigan 7: Tim Walberg , R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: No Clear Favorite

Michigan 9: Joe Knollenberg , R

One year ago: Leans Republican

Six months ago: Leans Republican

Today: Leans Democratic

Minnesota 1: Tim Walz , D

One year ago: Leans Democratic

Six months ago: Leans Democratic

Today: Democrat Favored

Minnesota 2: John Kline , R

One year ago: Safe Republican

Six months ago: Safe Republican

Today: Republican Favored

Minnesota 6: Michele Bachmann , R