By Louis Jacobson

PoliticsPA Contributing Writer

As Election Day nears, the latest installment of PoliticsPA’s House seat vulnerability rankings has shuffled a bit, but the general trend remains the same – lots of opportunities for the Republicans, and a load of worry for the Democrats.

This month’s rankings have a new No. 1 – freshman Democratic Rep. Kathy Dahlkemper, moving up from No. 3 – though each of the top three slots remains highly vulnerable to a Republican takeover.

Our ordering has remained broadly consistent for the past several months. But unlike late summer and early fall, when the Democrats’ peril seemed to increase in almost every race up and down the list, we see the level of peril remaining high, but not necessarily increasing. The GOP stands to gain between two and seven seats on Election Day.

As before, the big question is still whether national wave aiding Republicans drags down even Democratic incumbents in Pennsylvania who have taken great pains to insulate themselves from their party’s unpopular leadership through their voting records and their constituent service.

As in the past, our rankings include 10 lawmakers, listed in descending order of vulnerability. We’re considering the other nine seats in the delegation to be safe, though we reserve the right to add new names to the vulnerability list if circumstances shift. At this point, only Democrats in overwhelmingly favorable districts – mainly ones in and adjoining Philadelphia and Pittsburgh – have good reason to feel much job security.

Here’s the list:

1.Kathy Dahlkemper (D-3). Previous ranking: 3. Dahlkemper, the freshman Democrat who ousted GOP Rep. Phil English during the 2008 wave election, now faces a growing likelihood of defeat amid a wave in the opposite direction. A late-September Hill/America’s Natural Gas Alliance Midterm Election Poll had Republican Mike Kelly leading by 13 percentage points, 49 percent-36 percent. Dahlkemper’s opponents smell blood – not just the National Republican Congressional Committee but also the conservative 60-Plus Association. And Kelly is able to supplement the outside support with his deep pockets as a prominent car dealer. The weight of Dahlkemper’s support for the health care bill appears to be overriding Kelly’s weaknesses as a political newcomer. Time is running out.

2. Paul Kanjorski (D-11). Previous ranking: 1. Kanjorski’s is no longer the most endangered seat on our list. It’s not so much that the district has fallen back in love with the 13-term Democratic incumbent, but rather that he and his allies may be making some headway in decreasing the attractiveness of his Republican opponent, Hazleton Mayor Lou Barletta, through a series of hard-hitting ads by the Kanjorski campaign and the Democratic Congressional Campaign Committee. Still, Kanjorski has a steep climb: Two polls by the Wilkes-Barre Times-Leader newspaper have shown Barletta up by double digits, and the 11th District, full of older conservative Democrats, is fertile territory for the GOP wave.

3. Open seat (held by outgoing U.S. Rep. Joe Sestak). Previous ranking: 2. This seat may not be lost quite yet to the Democrats; a Monmouth University poll found that Republican Patrick Meehan leads Democrat Bryan Lentz, 49 percent-45 percent, with a nearly 4-point margin of error. Still, the well-known ex-U.S. Attorney Meehan still likely has the edge in this GOP wave environment

4. Patrick Murphy (D-8). Previous ranking: 4. The race in this Bucks County district has probably risen further in our rankings than any other. Just a few months ago, Murphy seemed relatively comfortable; now, he’s become highly endangered. A mid-September poll by Franklin & Marshall University had Murphy trailing former Rep. Michael Fitzpatrick, 49 percent – 35 percent among likely voters. (An internal Democratic poll showed him up.) Murphy, an Iraq War veteran, has been a strong fundraiser. But Fitzpatrick has been, too, and the NRCC is running ads in the district. To the extent that independent voters in this moderate, Philadelphia district are disgusted with the President Barack Obama and the Democratic Congress, Murphy is in dire straits.

5 (tie). Chris Carney (D-10). Previous ranking: 6 (tie). The question in this race is whether Carney and the DCCC can make GOP challenger Tom Marino unelectable. They are accusing Marino, a former U.S. Attorney, of a host of improprieties, and the attention may be curbing what had been a modest Marino surge from a few weeks ago. A poll by the Wilkes-Barre Times-Leader had Marino up, 40 percent-36 percent, but a Lycoming College poll had Carney up, 43 percent – 40 percent. Even Republicans have come to rue Marino’s primary win, feeling that the district’s Republican lean would have made it a reasonably easy pickup for any other candidate.

5 (tie). Mark Critz (D-12). Previous ranking: 5. We haven’t seen much recent public polling in this economically hard-hit district in southwestern Pennsylvania, but our sources say that Republican Tim Burns remains a viable threat to unseat Critz, who beat him in a May special election by a surprisingly large seven-point margin. Since then, Critz has distanced himself from his party’s leadership, which should help his prospects. The demographics of the district are a good fit with the kinds of places where the GOP should do well on Election Day, but Burns’ past inability to close the deal explains why this district ranks relatively low on our list.

7. Jason Altmire (D-4). Previous ranking: 8. Like the Critz seat, Altmire’s has favorable demographics for the GOP wave, but political novice Keith Rothfus seems to be low on the Republican priority list, likely due to Altmire’s lead in the money and the polls. Altmire has also been careful to distance himself from the Democratic leadership, including votes against the health care bill and the TARP bailout for Wall Street. At this point, Rothfus is largely on his own, and that means Altmire might manage to survive.

8. Charlie Dent (R-15). Previous ranking: 6 (tie). For months, Democrats have been high on the chances that John Callahan, the Bethlehem mayor, could oust the moderate Dent in this Lehigh Valley swing district. But the expected GOP wave is making Callahan’s task increasingly difficult. For the second straight ranking, we’re dropping this by a couple notches on our list.

9. Tim Holden (D-17). Previous ranking: 9. Holden is airing a positive biographical spot and an attack on state Sen. Dave Argall’s role in the disastrous 2006 legislative pay raise – not exactly the kind of approach you’d expect of a candidate desperate to preserve his political life. In fact, Holden has a good reason for this – with Argall underfunded and not catching fire, Holden remains the endangered Democrat most likely to survive.

10. Jim Gerlach (R-6). Previous ranking: 10. Manan Trivedi, a physician and Iraq veteran, is running an aggressive campaign, but Gerlach remains at the bottom of our vulnerability list due mainly to his party affiliation. Gerlach is not only a Republican in a Republican year, but a battle-tested one at that, having survived numerous prior Democratic takedown attempts. Also, the Philadelphia media market is pricey, making it hard for a newcomer to break through. Maybe Trivedi could try again in 2012.

Louis Jacobson, a staff writer with PolitiFact.com, has handicapped state races for the Cook Political Report, the Rothenberg Political Report, Roll Call, stateline.org and Governing.