The death of Rep. John Murtha will require a special election to replace him before November, according to Pennsylvania Law. The Washington Post reports:
According to state law, the governor has ten days once the vacancy is officially declared to decide on the date for the special election, which can come no sooner than 60 days following that proclamation.
That likely means the special election will be held on May 18, which is the date already set for federal primaries around the state. (Special elections costs the state huge sums of money and it's likely that Gov. Ed Rendell will choose to go with an already established election day to save some cash.)
There is a good chance that the Republican Party will pick-up another House seat in the special election. The Post notes:
Murtha's district is the only one in the country won by Sen. John Kerry (D-Mass.) in 2004 and by Sen. John McCain (R-Ariz.) in 2008, according to Republican sources, and that trend line coupled with the volatile national environment for Democrats ensures Republicans will heavily target the contest.
Ed Lasky points out:
Murtha's death makes Pennsylvania perhaps the most competitive state in the country when it comes to the battle for the House. Republicans will target the 4th, 7th, 8th, 10th, 11th and 12th districts while Democrats see opportunity in the 6th and 15th.
Special elections have been a disaster for the Democrats lately. If they hold Murtha's seat, that would stanch GOP momentum to a degree. On the other hand, a GOP victory would further weaken Obama's hold on Congressional Democrats.