House passage brings a likely chance of a rare House-Senate conference on the legislation, as the Senate has already passed a largely similar patent bill. But given this week's apparent breakdown in talks over a debt ceiling agreement, it is unclear how soon this work might begin. The White House has said it supports the legislation.

The biggest reform in the bill is a change in the U.S. from a first-to-invent to a first-inventor-to-file patent system. Proponents of this change have argued that this would be a step toward harmonizing the U.S. patent system with that used by most of the rest of the world.

But opponents argued that this change would put up new hurdles to people seeking patents, including small companies. They also argued it's unconstitutional.

The House held a rare debate Wednesday devoted to questions of constitutionality, in which members cited Article I, Section 8, Clause 8 of the Constitution. That clause says Congress has the power to "promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."

Several opponents warned that by putting in place a timely filing requirement, the bill violates this simple language in the Constitution, and would invite legal challenges that could rise to the U.S. Supreme Court. But these arguments failed to persuade most of the House, which on Thursday rejected an amendment to strike language making the change.

Another controversial issue involves Section 18 of the bill, which many argue would make it easier for financial institutions to challenge business method patents. Several members of both parties said this is a boon to banks that have grown too comfortable receiving boons in the last few years, but supporters of the language said the provision is needed because of the existence of many low-quality business method patents.

Efforts to strike Section 18 also failed in amendment votes Thursday.

Democrats argued generally that the bill does not do enough to ensure that patent application fees collected by the U.S. Patent and Trademark Office stay in that office, which could use the money collected to hire patent examiners and reduce patent backlogs.

And early in the debate, several Democrats and Republicans argued that the bill would even increase the deficit. Before leaving the Rules Committee, Republicans had to execute a maneuver by which they waived the "cut-go" rule in order to correct a drafting error in the House Judiciary Committee.

While Republicans argued that the fix was technical in nature, opponents of the bill from both parties used it -- unsuccessfully -- as a chance to try to redirect the bill back to the committee.