Something I just realized, from reading about the tightening results in NY-23 – prior to the two special elections, Pelosi had literally a one vote margin on the health care. From the article:
Before Owens was sworn in Friday, Rep. John Garamendi, a Democrat who won a special election in California, was sworn in Thursday. The two gave Pelosi the votes she needed to reach a majority of 218 and pass the historic health care reform legislation in the House.
The bill passed 220-215 late Saturday with the support of only one Republican. The Republican, Rep. Anh “Joseph” Cao of Louisiana, said he voted for the legislation only after seeing that Democrats had the 218 votes needed for passage.
This isn’t quite right; with both special election seats vacant, 217 would have provided a majority. If both seats had been claimed by opponents of health care, Pelosi could have held the vote before seating the new representatives. Without their two votes and without counting Cao, this would have left her with exactly 217 votes. Wow.