They sizzled in 2006. But can they sustain and perhaps gain in 2008?

The Democrat-controlled House that former Democratic Congressional Campaign Committee Chairman Rahm Emanuel built last year is entering its seventh month this week. A year from now, the campaign-speak about House seats will concern two things -- “cash on hand” and slogans with some phraseology containing the words “rubber stamp.”

Emanuel struck gold in the Keystone State in 2006, impressively picking off four Republican incumbents:

· Jason Altmire beat Melissa Hart in the 4th Congressional District

· Joe Sestak beat Curt Weldon in the 7th

· Patrick Murphy beat Mike Fitzpatrick in the 8th

· And Chris Carney unseated Don Sherwood in the 10th.

It turned Pennsylvania’s political landscape into a House of blues.

Stunning as the Democrats' victories were -- in very stable Republican districts won by George W. Bush -- the celebration of a House win always is short-lived. Already, incumbents must begin defending their seats.

The four won for a variety of reasons: Altmire because Hart refused to compete aggressively; Carney because of Sherwood's personal behavior; Murphy and Sestak largely due to the political environment -- voters moving away from Republicans.

So who's vulnerable?

Not Patrick Murphy. He probably has done the most to establish himself as a quality incumbent who deserves re-election -- certainly more so than the other three. From the work he has done pursuing a national veterans' cemetery in Bucks County to securing $1.1 million for Delaware River flood prevention and repairs he gets the importance of paying attention to local issues. The only veteran of the Iraq war serving in Congress, he also co-authored legislation for a 21st Century GI Bill of Rights.

Probably not Sestak either. His seat in the southeast near Philadelphia has been held by a Democrat in the past and, based on the district’s voting performance, likely will be very hard for the GOP to win back.

Jason Altmire of McCandless is a maybe. A default winner the first time, his vulnerability comes into play if former Pittsburgh Steeler Lynn Swann runs a top-notch campaign against him.

Chris Carney's seat in the northeast is probably most endangered. While much ado was made recently when U.S. Attorney Tom Marino dropped out of consideration, backbencher Dan Meuser is probably the better quality candidate anyway. He understands the issues, has charm and sports a sizeable personal checkbook. Marino was attractive, but this marks the second time in 10 years that he has floated his name only to pull out before his toe hit the water.

Then there are the pick-up opportunities high on the Democrats’ agenda; Republicans Tim Murphy of Upper St. Clair, Phil English of Erie, Jim Gerlach in Chester County and Charlie Dent in the Lehigh Valley.

This will be the first real test for the 18th District’s Murphy. Tough and hardworking, he has done a good job of taking enough centrist votes to appeal to Democrats; if he can get past ethical issues, he will be fine.

English, in the 3rd District, will need to step up his operations as he faces his first real challenge since 1996. And it comes as he has lost his top adviser Bob Holste to Rudy Giuliani’s presidential campaign. He has proven he can run aggressive, tough campaigns appealing to swing voters, just as he did in 1996 when Bill Clinton won the district and English won re-election.

Gerlach, from the Philadelphia collar counties of the 6th Congressional District, has had tough races with lots of money against him every time. Battle-tested, he is ready to go.

Dent, in the 15th District, is the most likeable of the four. He has experience winning tough races for the state House and state Senate; he coasted into his congressional seat in 2004 but got a real scare the last time. His is the most volatile congressional district in the state – truly purple -- competitive for both parties in registration and voter performance.

Americans sent Democrats to Washington to change policies. Yet the simple math is that they do not have a veto-proof majority in either House.

Top that with Congress’ cellar-dwelling approval rating and both parties face a challenge in 2008.

Pennsylvania once again will be in play in 2008. And as a politically “swinging” state that is the backbone of ticket-splitting Reagan Democrats, look for both parties to run hard here, as if every seat they’re seeking is wide open.