The judicially-created doctrine of obviousness-type double patenting (ODP) originated long ago as a shield to protect the public against unwarranted patent term extension (PTE). The Uruguay Round Agreements Act of 1994 (URAA) removed most of these concerns when it changed statutory term from 17 years from issue to 20 years from earliest effective filing date. By limiting patent families to a single 20-year term, the URAA eliminated the ability of patent owners to indefinitely extend the term of their invention by filing successive continuations claiming similar subject matter. After the URAA, all patents in a family are effectively limited to the 20-year term of the first-filed patent, plus an occasional modest term extension due to regulatory delays (PTE) or delays at the U.S. Patent and Trademark Office (USPTO) (Patent Term Adjustment (PTA)).

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