The Senate’s Standing Rules impose germaneness requirements on amendments only in certain circumstances. Specifically, Rule XXII states, “No dilatory motion, or dilatory amendment, or amendment not germane shall be in order” during post-cloture consideration of legislation (i.e. after three-fifths of the Senate duly chosen and sworn, typically 60, has voted to end debate). However, the rule itself does not provide a definition of germaneness. Rather, the very next sentence clearly states that the Presiding Officer shall decide “questions of relevancy” without debate and that the full Senate will determine germaneness on appeal of the Presiding Officer’s ruling. Similarly, Rule XVI precludes nongermane amendments to general appropriations bills, as well as legislative amendments (i.e. amendments not strictly limited to spending money). As with Rule XXII, the rule does not provide a definition of germaneness.
Precedents fill in the gaps in the Senate’s Standing Rules in such instances. For example, the definition of germaneness utilized by the Senate today when considering amendments (and by Graham during consideration of the defense bill) is a creature of precedent. As noted above, Rule XXII makes only a passing reference to the question of germaneness. Both the Presiding Officer’s rulings and any subsequent appeals create precedents that flesh out and define this germaneness standard. It is thus the cumulative outcome of these adjudicated questions of order that provides, in part, the definition of germaneness used in the Senate today.
According to a 1989 paper by the Congressional Research Service’s Stanley Bach, the Senate adjudicated 213 questions of order between 1965 and 1986. Of those, 159 (74.6%) involved determinations as to whether particular amendments were in order for floor consideration. Of these, 15.5% determined the germaneness of amendments proposed post-cloture or under unanimous consent agreements requiring that all amendments be germane.