During the fall, as President Barack Obama’s approval ratings started to drop, rumblings began that Democrats were in danger of losing a big part of the majority they won in the House in November 2006 and bolstered just last year.

At the time, these prognostications were premature in great part because Democrats were well-insulated by the utter lack of retirements among their Members. Without retirements, the GOP can have no real hope of making huge gains. Winning back seats with an incumbent running for re-election is difficult because even first-term or red-district Democrats have large war chests, requiring the National Republican Congressional Committee to spend considerable money to flip each seat. The lack of retirements has been the largest obstacle to the Republicans making a comeback.  

But things have changed in a hurry. In quick succession, four Democrats in even or Republican districts have announced their retirements — Rep. Dennis Moore in Kansas’ 3rd district, Rep. John Tanner in Tennessee’s 8th, Rep. Brian Baird in Washington’s 3rd, and, most recently, Rep. Bart Gordon in Tennessee’s 6th — putting three seats at risk of flipping to the GOP, with Gordon’s seat a near-lock to switch. 

Gordon’s loss is particularly shocking since he won easily last year and is chairman of a full committee. But his district went drastically to the right last year, with its Partisan Voting Index jumping to R+13 from R+4, according to the Cook Political Report.

These retirements constitute the Democrats’ worst nightmare, as the party’s ability to hold the line was their firewall to extensive losses in 2010. 

Using a simple five-point checklist of questions, we can attempt to forecast some of the next Members who could retire from seats that could then become competitive:

1. Seniority. Given that newer Members are likely to stick around, was the Member elected before 2004?

2. District PVI. Is the score D+3 or less?

3. Electoral Problems. Could the incumbent face a tough race in 2010, or is he or she in a district that will never be safe?

4. Committees. Is the Member either not on an A-committee — Appropriations, Energy and Commerce, Rules, or Ways and Means, or even if they are, do they have little hope of ever attaining a gavel? 

5. Age. Is the Member older than 65, or otherwise dealing with age or health-related issues?

Using these questions, we will highlight 10 Democratic Members who have at least some of these characteristics, and six bellwethers whose retirements, while unlikely, would portend terribly for the Democrats: 

• Rep. Marion Berry (Arkansas’ 1st district; R+8; elected 1996). Berry ran unopposed last year, but he watched as Arkansas lurched to the right, with his district going from D+1 to R+8 in one year; additionally, he will be 68 years old next year.

• Rep. Leonard Boswell (Iowa’s 3rd; D+1; elected 1996). Boswell will be 76 in 2010, with his chairmanship of the Agriculture Subcommittee on General Farm Commodities and Risk Management his greatest impetus for hanging in for another term; he is not positioned to ever chair the full committee.

• Rep. Lincoln Davis (Tennessee’s 4th; R+13; elected 2002). The entire state of Tennessee took a hard turn to the right last year, and while Davis won comfortably last year, at 66 and with no seniority on his committees (though he is on Appropriations), there are rumors that Davis could demur should an energetic Republican challenger materialize. Davis told Roll Call this week that he will seek re-election.

• Rep. Bob Etheridge (North Carolina’s 2nd; R+2; elected 1996). Etheridge, a low-key Member who decided against a Senate run next year, does have more than $1 million on hand and chairs an Agriculture subcommittee, but he will be 69 years old in 2010 and has little hope of ever chairing the full committee. 

• Rep. Paul Kanjorski (Pennsylvania’s 11th; D+4; elected 1984). Kanjorski’s district should stay blue, but Kanjorski, 72, faces a strong Democratic primary challenge and then a likely rematch with Hazleton Mayor Lou Barletta (R), who has a national following; furthermore, even though he is next in line to chair Financial Services, it is unlikely Rep. Barney Frank (D-Mass.) will relinquish that gavel anytime soon, even if Rep. John Conyers (D-Mich.) were to retire, opening up the Judiciary chairmanship, where Frank retains seniority.

• Rep. Jim Marshall (Georgia’s 8th; R+10; elected 2002). Marshall won with surprising ease last year, but in this district he will never be safe, and if Republicans hold the governor’s mansion as expected, he can count on the state Legislature making his district even more inhospitable in 2012. 

• Rep. Solomon Ortiz (Texas’ 27th; R+2; elected 1982). Ortiz is third in line to chair Armed Services, but his ascendance would take the retirements of both Reps. Ike Skelton (D-Mo.) and John Spratt (D-S.C.); he will also be 73 next year. 

• Rep. Ike Skelton (Missouri’s 4th; R+14; elected 1976). Skelton chairs the Armed Services Committee and remains a legend in his Western Missouri district; it is, therefore, hard to envision him quitting or ever losing, but the big question is how Skelton, 78, will react to a potentially hard GOP challenge for the first time since 1982.

• Rep. Vic Snyder (Arkansas’ 2nd; R+5; elected 1996). Like Berry, Snyder didn’t face a major-party opponent last year, but his district — along with the rest of the state — moved to the right. With little money and Republicans gunning for him, his Armed Services subcommittee chairmanship might not be enough to persuade him to stay and fight.  

• Rep. Bart Stupak (Michigan’s 1st; R+3; elected 1992). This seat is electorally safe, and while Stupak sits on Energy and Commerce, his Subcommittee on Oversight and Investigations has been neutered since President Barack Obama was inaugurated and Stupak’s close ally Rep. John Dingell (D-Mich.) was ousted from the full chairmanship by Rep. Henry Waxman (D-Calif.). Also watch to see whether health care reform passes without his amendment restricting federal funding for abortions. 

There are also a handful of Members whose retirements, while currently unlikely, would be a terrible sign for Democrats. 

Let’s rank the bellwether retirement watch in two tiers. In Tier Two are Reps. Tim Holden (Pa.), John Murtha (Pa.), and Spratt. Spratt is a full committee chairman, Holden is next in line to chair Agriculture and Murtha heads the powerful Appropriations Subcommittee on Defense. Should any of them head off, their districts would be badly endangered. 

Reps. Chet Edwards (Texas), Earl Pomeroy (N.D.) and Gene Taylor (Miss.) make up Tier One. All three have strong seniority on good committees, and most importantly, none of them are yet 60. Each of their seats is a lock to become Republican if they retire. More significantly, though Edwards released a statement this week insisting he’s staying put, any of their retirements would cast a devastating pall on the caucus and likely signal a wave of departures.

Mark Greenbaum is a writer and lawyer in Washington, D.C.