http://leahy.senate.gov/issues/health/VermontVoicesVocab.html#Shell_Bill"Shell Bill
Article I, Section 7, clause 1 of the U.S. Constitution is known generally as the "Origination Clause" because it requires that "All Bills for raising Revenue shall originate in the House of Representatives; but the Senate may propose or concur with amendments as on other Bills." This clause is generally understood to prohibit the Senate from originating any measure that includes a provision for raising revenue or proposing any amendment that would raise revenue to a non-revenue measure. However, the Senate can amend a House-originated revenue measure as it sees fit.
In order to comply with this clause, the Senate typically takes a revenue-raising bill that has already been passed in the House of Representatives and amends it (or replaces it entirely) with its own bill. The original bill is often referred to as a "shell bill." It is a part of our legislative process that has been utilized by legislators from both sides of the aisle. For example, a bill on the Alternative Minimum Tax was used as a shell bill for the 2006 Immigration reform, and the Housing and Economic Recovery Act of 2009 was attached to a shell bill that started out as green-jobs legislation.
In addition to being relatively common, this procedure is legal, constitutional, and has been upheld by the U.S. Supreme Court.
In the case of health care reform legislation the Senate will take up H.R. 3590, the Service Members Home Ownership Tax Act of 2009 which modifies the first-time homebuyers credit in the case of members of the Armed Forces."Hoyer Press Conference - since this conference they used another House bill as stated above by Leahy.
http://majorityleader.gov/docUploads/PenandPad100609.pdfpage 5 and 6
"...Let me stop with that and try to answer some of your questions.
Q Leader Hoyer, the Senate has considered using H.R. 1586, a bill that already passed the House, to tax some bonuses received by TARP recipients as a shell to contain their -- to hold their health care bill; in other words, to amend 1586 to include their entire language of their health bill and then send it to the House. If that happens, will you rule out holding a direct vote on the Senate health care package in that form, which will send it to the President without amending it or sending it to conference?
Mr. Hoyer. Well, I won't rule it out or in because I don't know what that package is, nor does the Senate at this point in time. They still have the necessity to harmonize the health bill and the finance bill. So it would be premature for me to answer that question because I don't know exactly what form it is going to be in.
Having said that, obviously, the reason they are doing that, as you well understand, is because there are component parts of their bill that would need to be generated in the House. It would need to under the Constitution be initiated by the House. So that is a House bill, and that is a useful vehicle for them to use. But it would be premature to say whether I would support moving that as is at this point in time.
Q So it depends on the context of the bill, not the way they get it to the House.
Mr. Hoyer. Yeah. Constitutionally there are some reasons why it has to be a House bill; however, content will be critical in what action the House takes..."