Section 203: research must serve a military purpose
Public Law 91-121 of 19 November 1969 (the Military Authorization Act for fiscal year 1970) forbids in section 203 the use of the funds it authorises for any research project or study that lacks «a direct and apparent relationship to a specific military function or operation».
Why it matters
The condition on defence research money became written and checkable: not «useful some day» but «a direct relationship to a specific function». For laboratories living on Department of Defense funds this is what is later called the Mansfield amendment. This is an editorial assessment: the law names no field and no programme.
The text: Public Law 91-121, 19 November 1969, 83 Stat. 206, section 203 in Title II (research, development, test and evaluation): «None of the funds authorized to be appropriated by this Act may be used to carry out any research project or study unless such project or study has a direct and apparent relationship to a specific military function or operation.» What the record does not claim. This is an authorization act, not an appropriation act as the project's brief has it: the funds in question are those «authorized by this Act», that is, for fiscal year 1970. The name Mansfield does not stand in the statute text read; the legislative history, the amendment's sponsor and how many projects were closed were not read. The words «artificial intelligence» and «ARPA» do not occur on the pages read, so the record does not say the law touched those programmes. The formula was softened the following year: see the record on section 204 of Public Law 91-441.