It should come as little surprise that as the House battleground has shrunk considerably in recent years due to redistricting efforts, the number of Members considered vulnerable based on their election performance has also proportionally decreased.

Therefore, as both parties pore over last week’s election results and begin to assemble their respective target lists for the 2006 cycle, they will start from one of the most limited playing fields in recent memory.

This year only 37 new or returning Members garnered 55 percent of the vote or less — the fewest number in at least four election cycles. That total is nearly half what it was in the 2000 cycle, when 62 Members were elected with 55 percent or less.

Fifty-five percent is considered the low water mark that traditionally has signaled vulnerability in the next election cycle.

In 2002, following the latest round of redistricting that served to shore up seats for both parties, 49 candidates received 55 percent or less. The 55 percent and under club also included 49 Members in 1998.

As further proof of the diminishing playing field, eight candidates elected in 2002 received 50 percent or less, but Reps.-elect Mike Sodrel (R-Ind.) and Randy Kuhl (R-N.Y.) are the only Members of the 109th Congress who will have that distinction. Sodrel defeated three-term Rep. Baron Hill (D-Ind.) with 49 percent of the vote, while Kuhl won an open seat with 50 percent, besting his opponent by 9 points.

Among the 37 on the 55 and under list, some of the most vulnerable targets for 2006 are the 10 freshman Members who won competitive open-seat contests.

Those on the list considered most likely to face competitive challenges are Reps.-elect John Salazar (D-Colo.) and Dave Reichert (R-Wash.), who won with 51 percent and 52 percent, respectively.

Another likely target and addition to the list of 55 and under is New York Assemblyman Brian Higgins (D), who had yet to be declared the official winner in the 27th district race as of press time Friday.

He led Erie County Comptroller Nancy Naples (R) by more than 4,000 votes of the 271,000 cast, but between 8,000 and 15,000 absentee and provisional ballots had yet to be counted, and Naples has requested that a judge supervise the count of the remaining votes. Republicans privately concede, however, that Higgins’ margin is all but impossible to overcome.

The other four freshmen on the 55 and under list defeated incumbent Members, but only two of them are likely to be targeted in 2006.

While Sodrel may face a competitive challenge — and there is already some talk that Hill might seek a rematch — the 9th district has always slightly favored the GOP, and it will no doubt be an uphill battle for Democrats to retire Sodrel before another round of redistricting. Rep. Pete Sessions (R-Texas) may also face a rematch with departing Rep. Martin Frost (D-Texas), who was defeated handily in the redistricting created Member-versus-Member matchup.

Republicans, will no doubt make Melissa Bean, who defeated 17-term Rep. Phil Crane (R-Ill.) in a suburban Chicago district that favors the GOP, one of their top targets next cycle.

Bean defeated Crane 52 percent to 48 percent after she made the incumbent’s fitness for office the centerpiece of the campaign.

The other two successful challengers on the list this year, incoming Reps. Ted Poe (R-Texas) and John Barrow (D-Ga.), are not likely to be targeted if their current districts remain intact.

Barrow defeated Rep. Max Burns (R-Ga.) in a district that was tailor-made for a Democrat to begin with, and Poe ousted Rep. Nick Lampson (D-Texas) after a re-redistricting effort shored up the district for the GOP.

After Democrats lost House seats for the second straight cycle last week, the 55 and under list appears to bring some good news for the party considering that it is made up of 24 Republicans and 13 Democrats.

Democrats could also further expand that playing field by revisiting a number of missed opportunities from this current cycle.

Of the eight Members who received 50 percent or less in 2002, all are returning to the House and only two made the 55 percent or less list this year — Reps. Chris Chocola (R-Ind.) and Dennis Moore (D-Kan.).

While Chocola did not face a top-tier challenge, he still managed only 54 percent of the vote in the swing 2nd district. Moore got 55 percent in a rematch from 2002, his largest percentage yet since winning in 1998.

Democrats targeted freshman Reps. Rick Renzi (R-Ariz.) and Bob Beauprez (R-Colo.), but both ended up winning by wide margins and avoiding the 55 and under list. Freshman Rep. Mike Rogers (R-Ala.), who won with only 50 percent of the vote in 2002, faced nominal opposition and won a second term with 61 percent last week.

The list also includes more than a handful of veteran incumbents who sit in swing districts and are perennial targets.

These Members — such as Moore, Reps. Julia Carson (D-Ind.), Leonard Boswell (D-Iowa), Robin Hayes (R-N.C.), Heather Wilson (R-N.M.) and John Hostettler (R-Ind.) — make repeat appearances on the list but have proved difficult to beat in the past.

Still, Hill’s defeat this year does serve as a reminder of their continual vulnerability. Hill had never received more than 54 percent of the vote since being elected in 1998.

Freshman Rep. Jim Gerlach (R-Pa.), who received 51 percent of the vote for the second straight cycle, appears on track to join that group of perennial targets. Hotly contested gubernatorial and Senate races in the Keystone State in 2006 make it all the more likely that Gerlach will have another tough fight on his hands.

While they may never win by large margins, there are those on the 55 and under list who are considered unlikely to be top targets again — or at least not until after the next decennial reapportionment and redrawing of district lines takes place in 2010.

While Rep.-elect Geoff Davis (R-Ky.) received 55 percent of the vote last week in picking up the seat of retiring Rep. Ken Lucas (D-Ky.) — a perennial member of the 55 and under club — Democrats are not expected to challenge for that seat again before the next round of redistricting.

Democrats are also unlikely to aggressively challenge freshmen-to-be Thelma Drake (R-Va.) and Jeff Fortenberry (R-Neb.), just as the GOP isn’t necessarily going to be gunning for Reps.-elect Emanuel Cleaver (D-Mo.) and Jim Costa (D-Calif.). All four won open-seat races in districts that clearly favor one party over the other.

But Democrats argue they had some success in expanding the playing field beyond those Members who appeared vulnerable after the 2002 elections. They point to Rep. Christopher Shays (R-Conn.), Rep. Mark Kennedy (R-Minn.) and the entrenched Crane as examples of Members who did not appear to be particularly vulnerable at the start of this cycle. Both Shays and Kennedy won with less than 55 percent.