In recent developments:
In Illinoios, State treasurer Alexi Giannoulias (D) has established an exploratory committee to run for the seat now held by Sen. Roland Burris (D). Burris has been a controversial pick from the beginning, and it is not clear if he will run in 2010. Other candidates are considering getting into the contest.
In Kansas, now that popular Gov. Kathleen Sebelius (D) has been appointed Secretary of Health and Human Services, she is no longer in contention for the Senate seat of Sen. Sam Brownback (R), who is retiring. The winner of a Republican primary for the seat will be Senator from Kansas: Democrats have not won a Kansas Senate seat since 1932.
In Kentucky, things get curiouser and curiouser. Senate Republicans are running far away from Sen. Jim Bunning (R), who is considered one of the weakest incumbent Republicans. He has responded by attacking Republican Senatorial Campaign Committee Chairman Sen. John Cornyn (R-TX) and Senate Minority Leader Mitch McConell (R), also of Kentucky. There were even reports that Bunning threatened to quit his seat and let the Democratic governor appoint his replacement.
In Ohio, Democrats now face at least a three-way primary between Lt. Gov. Lee Fisher, Secretary of State Jennifer Brunner and state Rep. Tyrone Yates. Republicans appear to have settled on ex-U.S. Rep. and ex-Office of Management and Budget director Rob Portman (R), who declared for the seat almost immediately after incumbent Sen. George Voinovich (R) announced he would not run again.
In Pennsylvania, former Rep. Pat Toomey (R), who lost a close primary challenge to incumbent Sen. Arlen Specter (R) in 2004, had changed his mind and may now seek a new Senate contest rather than run for Governor. No prominent Democrat has yet popped up to announce a run.
It is much too early to predict elections two years from now, but there are some known facts and early movement in key contests.
1. Number of seats up in 2010: Republicans again have to defend more seats than Democrats, 19 seats compared to 17.
2. Retirements: At this point, five GOP Senators have announced their retirements at the end of this term, compared to only one Democrat. Open seats are frequently highly competitive.
3. Newly-appointed Senators: There will be four Democratic seats previously held by invulnerable incumbents with names like Obama, Biden, Clinton and Salazar that will feature appointed incumbents in office for fewer than two years. The effect of these appointments is to make each seat more competitive.
4. Candidate recruitment: Both parties are looking for strong candidates to run, but already both have also suffered disappointments as favored candidates declined to enter the races.
The major imponderable: How popular will President Barack Obama be in November 2010? Many mid-term elections become referenda on the incumbent President’s party.
Some of the early battleground states:
California: The nation’s largest state only becomes a battleground if Gov. Arnold Schwarzenegger (R) decides to challenge Sen. Barbara Boxer (D). Even so, she should face spirited competition.
Colorado: Political newcomer Michael Bennet (D) was selected to replace Sen. Ken Salazar (D), the new Secretary of Interior. He is well-regarded by insider circles for his job as superintendent of Denver public schools and other work but is little known across the state. Former Colorado House speaker Andrew Romanoff (D) may challenge Bennet in a primary. Republicans are sure to mount a stiff challenge. Polls point to a close contest.
Connecticut: The chairman of the Senate Banking Committee, Sen. Chris Dodd (D) is in trouble. His sagging poll numbers are in part due to the banking crisis (he is chairman of the Senate Banking Committee) and in part to what looks like sweetheart real estate deals. While the state is strongly Democratic, a March 2009 poll showed that Dodd would get a strong challenge from former Rep. Rob Simmons (R), who has announced he is running.
Delaware: Sen. Ted Kaufman (D), Sen. Joseph Biden’s former chief of staff, has announced he will hold the seat for only two years. Attorney General Beau Biden, one of Biden’s sons, is expected to announce a run after he returns from an Iraq deployment. Republicans would like popular U.S. Rep. Mike Castle to run. Castle will be 71 in 2010, which would set up a strong contrast between himself and the much younger Beau Biden. However, a March 2009 poll showed Castle leading Beau Biden.
Florida: Both parties suffered recruiting disappointments for this race. The GOP hoped that former Gov. Jeb Bush (R) would run, and Democrats tried to persuade Chief Financial Officer Alex Sink (D) to run for the seat of Sen. Mel Martinez (R), who announced his retirement. A slew of other candidates are considering the contest, including U.S. Rep. Kendrick Meek (D) and former Florida state Speaker Marco Rubio (R). At this point, the race is a toss-up.
Illinois: Controversial Governor Rod Blagojevich’s (D) appointment of Sen. Roland Burris (D) embarrassed state and national Democrats. It is not clear whether or not 71-year old African American Roland Burris will run in 2010. State treasurer Alexi Giannoulias has established an exploratory committee and ex-Commerce Secretary William Daley (D) may run. The GOP is recruiting Chicago suburban U.S. Rep. Mark Kirk (R) to run.
Kansas: Sen. Sam Brownback (R), currently serving his second term in the U.S. Senate, has kept his promise to retire after two terms. Two GOP House members, Reps. Todd Tiahrt and Jerry Moran have indicated they will run in a primary against each other. That primary winner is almost surely the general election winner: Democrats have not won a Kansas Senate seat since 1932.
Kentucky: Two-term incumbent Sen. Jim Bunning (R) won by only 23,000 votes in 2004, a strong Republican year, and is considered highly vulnerable. Indeed, some Republicans are urging Bunning to retire rather than risk defeat. Bunning had only $150,000 in the bank at the end of December. Lt. Gov. Dan Mongiardo , who ran in 2004, has declared he will run. Other Democrats are considering the race, including, state Rep. Ben Chandler, state Attorney General Jack Conway (D) and Auditor Crit Luallen (D).
Louisiana: Democrats have been targeting Sen. David Vitter (R) since Mr. Family Values’ name was found in the D.C. Madam’s list of prostitutes’ customers. Vitter may get a primary challenge and – almost certainly – will receive a strong general election opponent.
Missouri: Sen. Kit Bond (R), who beat back a series of highly credible Democratic challengers over the years, has announced his retirement. Secretary of State Robin Carnahan (D), the daughter of a governor and senator and brother of a congressman, is the early Democratic frontrunner. Early polls show her with a narrow lead over both potential Republican opponents, U.S. Rep. Roy Blunt (R) and ex-state treasurer Sarah Steelman (R). This is probably a toss-up race.
Nevada: Republicans knocked off Senate Democratic leader Tom Daschle in 2004 and hope to repeat their victory by defeating Senate Democratic leader Harry Reid (D) from Nevada in 2010. In 2008, Reid helped defeat one potential challenger, U.S. Representative Jon Porter (R), and Lieutenant Governor Brian Krolicki’s (R) already has legal problems, but the GOP will almost surely find a serious challenger to contest Reid’s seat. While Reid won handily in 2004, he won by only 428 votes six years before. At the end of November, Reid had $3.3 million in the bank. The National Republican Senatorial Committee began running attack ads against Reid in January 2009.
New Hampshire: This state has been going increasingly Democratic with the defeat of both Republican House members in 2006 and Sen. John Sununu in 2008. Democrats are optimistic about winning the seat in 2010, particularly now that the seat is open with Senator Judd Gregg (R) saying he will retire.   Rep. Paul Hodes (D) has declared while U.S. Rep.Carol Shea-Porter has announced she will not run.
New York: Gov. David Paterson’s selection of little-known U.S. Rep. Kirsten Gillibrand (D) from upstate New York to replace former Sen. and now Secretary of State Hillary Clinton could lead to stiff primary opposition from U.S. Rep. Carolyn McCarthy (D), who objects to Gillibrand’s pro-gun position, or from a Republican like U.S. Rep. Peter King. Gillibrand is a ferocious fundraiser and a formidable campaigner, but she has to move quickly to get herself known across the Empire state. The state’s Democratic leanings make her the early favorite.
North Carolina: North Carolina went for Barack Obama in 2008 and ousted Sen. Elizabeth Dole (R) with the election of Sen. Kay Hagan (D). Now Democrats have turned their sights on Sen. Richard Burr (R). State Attorney General Roy Cooper (D) is considering a challenge. Polling shows Burr only slightly ahead of these and other potential challengers.
North Dakota: Sen. Byron Dorgan (D) will breeze to re-election unless Gov. John Hoeven (R) gets into the contest.
Ohio: Ex-U.S. Rep. and ex-Office of Management and Budget director Rob Portman (R) declared his candidacy immediately after the announced retirement of Sen. George Voinovich (R). He may run opposed for the GOP nomination. Democrats face a primary between Lt. Gov. Lee Fisher, Secretary of State Jennifer Brunner and state Rep. Tyrone Yates. Both the primary and general election are wide open.
Pennsylvania: MSNBC’s “Hardball” host Chris Matthews decided against running, but incumbent Sen. Arlen Specter (R) will have ample competition, perhaps from members of both parties. Club for Growth president Pat Toomey, who almost defeated Specter in a 2004 primary, is now expected to seek a rerun. Pennsylvania, which has been trending Democratic, will almost certainly produce a tough Democratic challenger.
17 Democratic seats
Evan Bayh (IN)
Michael Bennet (CO)
Barbara Boxer (CA)
Roland Burris (IL)
Christopher Dodd (CT)
Byron Dorgan (ND)
Russell Feingold (WI)
Kirsten Gillibrand (NY)
Daniel Inouye (HI)
Ted Kaufman (DE) – retiring
Patrick Leahy (VT)
Blanche Lincoln (AR)
Barbara Mikulski (MD)
Patty Murray (WA)
Harry Reid (NV)
Charles Schumer (NY)
Ron Wyden (OR)
19 Republican seats
Robert Bennett (UT)
Christopher Bond (MO) – retiring
Sam Brownback (KS) – retiring
Jim Bunning (KY)
Richard Burr (NC)
Tom Coburn (OK)
Mike Crapo (ID)
Jim DeMint (SC)
Chuck Grassley (IA)
Judd Gregg (NH) – retiring
Johnny Isakson (GA)
Mel Martinez (FL) – retiring
John McCain (AZ)
Lisa Murkowski (AK)
Richard Shelby (AL)
Arlen Specter (PA)
John Thune (SD)
David Vitter (LA)
George Voinovich (OH) – retiring