United States patent law was established "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;" as provided by the United States Constitution. The American patent system is authorized by Article One, Section 8(8) of the U.S. Constitution which states:
- The Congress shall have 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;
In the U.S., a patent is a right to exclude others from making, using, selling, offering for sale, exporting components to be assembled into an infringing device outside the U.S., importing the product of a patented process practiced outside the U.S., inducing others to infringe, offering a product specially adapted for practice of the patent, and a few other very carefully defined categories. The distinctions between what patent rights include are complex. For example, merely thinking about an invention or drawing a diagram is not an infringement. Likewise, research for "purely philosophical" inquiry is not an infringement. Sometimes, this analysis can be much more sophisticated and difficult: i.e., research directed to commercial purposes may be an infringement but may not be when the research is directed toward obtaining approval of the Food and Drug Administration for introduction of a generic version of a patented drug.
Under current U.S. law, the term of patent is 20 years from the earliest claimed filing date (which can be extended via Patent Term Adjustment and Patent Term Extension). For applications filed before June 8, 1995, the term is either 17 years from the issue date or 20 years from the earliest claimed domestic priority date, whichever is longer.
Under Title 35 of the United States Code, the patentability of inventions is defined under Sections 100-105. Most notably, section 101  sets out subject matter that can be patented; section 102  defines novelty and loss of right to patent; section 103  lists what constitutes non-obvious subject matter.
The United States Constitution, Section 8, allows Congress to grant patents: "by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries" without limiting such rights to product developers. Just as there is no legal requirement that owners of real property develop their vacant land, there is likewise no legal requirement that patent owners develop their inventions.
Since the inception of patent laws in keeping with the Constitution, the U.S. Congress implemented these protections as a "first to invent" system. This type of system was markedly different from other national patent laws: the person determined to be the first inventor was deemed the actual inventor regardless of who happened to file first. However on September 16, 2011, the 112th Congress replaced the "first to invent" system with the "first inventor to file" system through the enactment of the Leahy-Smith America Invents Act on September 16, 2011. This new system is to be fully implemented by March 2013. The provisions of the law are laid out in Title 35 of the United States Code (U.S.C.) and give authority for the United States Patent and Trademark Office. The goal of this revision has been stated to be the harmonization of U.S. law with other countries' patent laws.
Pre-grant publication (PG Pub)
Since the American Inventors Protection Act, the United States Patent and Trademark Office publishes patent applications 18 months after they are filed for all applications with an effective filing date after November 28, 2000. This time limit can be extended under certain circumstances for an additional fee. The applications may be published before a patent has been granted on them if the patent is not granted within the 18 month time frame. Applicants can opt out of publication if the applicant will not be prosecuted internationally.
International Trade Commission (ITC)
In the United States, a patent holder may wish to pursue a cause of action in the ITC instead of, or in addition to the court system. In contrast to courts who have a wide range of remedies at their disposal, the ITC can only do one thing when it comes to patent infringement: grant or deny injunctive relief by ordering to keep infringing products from being imported into the United States. In some cases, this may provide a quicker resolution to a patent owner's problems.
Patents as property
According to Article One, Section 8(8) of the U.S. Constitution, Congress is granted the power to secure for limited times to ... inventors the exclusive right to their ... discoveries. Therefore, patents implementing that provision would have to grant temporary rights residing only in the inventors. Nonetheless, patents are now treated like property rights, so that they may be sold, licensed, mortgaged, assigned, transferred, given away, abandoned, actively developed, or held as investments without being developed. Just as there is no legal requirement that owners of real property develop their vacant land, there is likewise no legal requirement that patent owners develop their inventions.
fr:Droit des brevets aux tats-Unis ja: