Not good for House Republicans.

Rep. Jim Gerlach has told National Republican Congressional Committee officials that he is running for governor, a GOP source confirmed Tuesday, making his competitive southeastern Pennsylvania district a prime Democratic pick up opportunity in 2010.

The Allentown Morning Call first reported that the four-term Republican has opted to run for governor, ensuring that his suburban Philadelphia 6th district seat will be a top battleground next year. According to the newspaper report, Gerlach is expected to make his gubernatorial announcement at some point Tuesday.

Rumors abound that the Pennsylvania GOP and/or the NRSC are flirting with both Jim Gerlach and Tom Ridge.

We know Tom Ridge cannot win in Pennsylvania again in a Republican Primary because of the changed dynamics and demographics from the last time he ran. But what of Jim Gerlach?

The PAGOP and NRSC are flirting with him because Gerlach regularly wins re-election as a Republican in D +2 districts. They forget, however, that Pat Toomey did the same — and with larger margins.

In fact, in 2002, the year Toomey and Gerlach were both on the ballot in D +2, Toomey got 57.4% of the vote and Gerlach got 51% of the vote. Toomey did so without selling out his conservative values. Not so with Gerlach.

In fact, and this is key, Gerlach actually has a more liberal voting record on issues Pennsylanians care about than Arlen Specter. If Specter cannot get out of a Republican primary, how on earth could Gerlach? The answer is he can’t.

Consider these issues:

• Gerlach voted for the Medicare Prescription Drug Act.
• He voted for the Bridge to Nowhere.
• He voted to allow Fannie Mae and Freddie Mac to continue borrowing money from the Treasury.
• He voted for the mortgage bailout program.
• He voted for TARP
• He voted against the right of workers to cast a secret ballot for unionization.
• He voted against drilling in ANWR.
• He voted against the same-sex marriage ban.
• He voted against lifting the moratorium on natural gas production.
• He voted for outrageous pork projects like California’s Mule and packers, Missouri’s Jazz Mueseum, Maine’s Lobster Institute, and Houston’s zoo.

While these issues may not matter in a general election in Pennsylvania, they matter greatly in a Republican Primary in Pennsylvania and each of these votes works in Pat Toomey’s favor.

So the question is this: do the NRSC and PAGOP want to spend resources trying to beat Pat Toomey in the primary or do they want to focus on beating Arlen Specter? Because if they rough up Toomey now, they can’t beat him, but they make him very vulnerable.

In the meantime, there are more than 400 days before the 2010 general election. The situation is not static. The historic trends will most likely work in Toomey’s favor.