Martin Index

Luther Martin was a Maryland delegate to the convention that drafted the U.S. Constitution in 1787. He was hostile to proposals that would substantially strengthen the central government and give larger states greater representation than smaller states. Martin left the convention before it had finished its work, and he subsequently opposed ratification of the Constitution.

Martin delivered a report on the work of the Constitutional Convention to the Maryland State Legislature. In this report, which was also published as a pamphlet for use in the Antifederalist cause, Martin (1787/1937) argued that

Martin assumed that each state delegation would cast its votes as a bloc, and he went on to count up various voting combinations of states in order to support his claim. His objection to apportioning seats proportionally to population clearly anticipated one of the fundamental propositions of modern voting power analysis— namely, that voting power is not the same as voting weight (e.g., seats).

When William Riker discovered Martin's argument, he thought it sufficiently insightful to be characterized as “the first power index,” though [Page 402]Martin never proposed a summary measure of voting power. Moreover, while voting power may be highly disproportional to voting weight, it need not be so and, under the provisional apportionment of House seats to which Martin referred, each state's share of Banzhaf voting power is in fact closely aligned with its seat share. However, if Martin had focused on the two-stage voting power of individual members of the House, his objection would have been well founded, as each of the 10 Virginia members would have had more than two and one half times the Banzhaf voting power of the lone Delaware member.

While Martin's expectation that state delegations in the House would act as blocs was not borne out, state electoral votes (for President) would soon be cast in blocs, and the U.S. Electoral College has subsequently been one of the principal institutions to which voting power analysis has been applied.