Constitutional?
You make the call! First, a wrap-up from the Rude Pundit:

So, like, the AP story, the CNN story, the Fox "News" story and others all say that the Senate "unanimously" passed the thank-Christ-we're-not-talking-about-Social-Security Terry Schiavo bill. Technically, this is true. But all these articles fail to mention what the Miami Herald does distinctly note: "Only three members were on the floor and the bill's prime sponsor, Republican Sen. Mel Martinez of Florida, served as presiding officer." And those three members proudly raised their voices, and yes, technically the bill passed unanimously, just as technically Terry Schiavo is still "alive."

Which brings up the question--how many Congressmen make up a quorum?

Each House shall be the Judge of the Elections, Returns and Qualifications of its own Members, and a Majority of each shall constitute a Quorum to do Business; but a smaller Number may adjourn from day to day, and may be authorized to compel the Attendance of absent Members, in such Manner, and under such Penalties as each House may provide.

That sounds like it's more than three.

Idiots.