Can claiming a foreign priority date serve as the effective prior art date under 102(e)?

Claiming a foreign priority date cannot serve as the effective prior art date under 102(e) for a U.S. patent application unless the U.S. filing date is within one year of the foreign filing date. The one-year rule is specifically designed to provide applicants with a grace period during which they can file a patent application in the U.S. based on a previously filed foreign application without losing their rights to the invention. Under 35 U.S.C. § 102(e), a U.S. patent application must reference its own U.S. filing date for purposes of determining prior art against other applications and patents. Therefore, if the U.S. filing does not occur within that one-year window, the foreign priority filing date cannot effectively be used, thus emphasizing the necessity of the timing of the claim for it to be considered valid prior art.