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Tuesday, June 15, 2021

Jack Weinstein

Judge Weinstein passed away today at the age of 99. There will be many tributes to him, especially for his work on Brown. Let me just share a brief personal story about him.

I never met the Judge. But after my first book came out, I found in my mail one day a handwritten note from him saying that he read the book and enjoyed it. I was astonished because I'd never met him, never communicated with him, and my book wasn't exactly a best seller.

I sent him a thank-you note, and when my second book came out I sent him a copy. He read that too and wrote me about that. At that point I concluded that he might be a good luck charm of sorts, so I sent my third and fourth books to him as well. And he wrote back each time with some thoughts, though of course by now he was in his 90s. Alas, I cannot send him my next book. RIP

Posted by Gerard Magliocca on June 15, 2021 at 03:49 PM | Permalink


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Posted by: poppy playtime | Feb 24, 2022 4:45:23 AM

Prof. Banzhaf, please stop digging. 1) The first comment you responded to is Hugh's, not Joe's. 2) Joe's actual comment ("Clearly you have to dedicate the next book to him instead") was directed to Gerald ("you") and about you ("him". It was intended to point out and ridicule your own self-flattery, upon which your second comment effectively doubles down. 3) While everyone Googles themselves, it takes a special kind of person to catalog and rank the results for the purposes of highlighting his or her own importance.

Please. Stop.

Posted by: Sad-anon | Jun 17, 2021 11:38:09 AM

Joe's comment “...today it’s widely known as the 'Banzhaf Index of Voting Power' ..." In fact it is usually known as the Penrose-Banzhaf measure, Penrose being the first one to advance it, in the 1940s” is incorrect on two different grounds.


If one does a one-month Google search for “Penrose-Banzhaf measure” or “Penrose-Banzhaf,” each yields only a handful of returns.

But a similar search for the “Banzhaf Index” yields many pages - no comparison.

Similarly, using Google Scholar for articles since 2017, here are the results:
“Penrose-Banzhaf measure” = 6
“Banzhaf Index of Voting Power” = 16
“Banzhaf Index” = over 500

Again, not even close! So it’s hard to claim that it’s “usually known . . .”


Although both the Penrose-Banzhaf measure and the Banzhaf Index of Voting Power have to do with voting, they actually seem to measure two entirely different things.

For example, according to a summary in Wikipedia (based upon several cited works):

“Penrose developed the Penrose method, a method for apportioning seats in a global assembly based on the square root of each nation's population. Such a voting system is based on the voting power of any voter (measured by the Penrose–Banzhaf index) decreasing with the size of the voting body as one over its square root. See also Penrose square root law. “

In other words, his works seems to deal with and show, for example, that the ability of a voter under our electoral college to determine for whom his electoral votes will be cast (under the winner-take-all rule in effect in most states) is not inversely proportional to the state’s population, but rather to the square root of the state’s population. Under that system, each individual citizen voter is able to case ONLY ONE VOTE.

In contrast, the Banzhaf Index uses computer-based (usually) calculations to determine how much voting power each legislator or voter has when they are permitted to cast DIFFERENT NUMBERS of votes - NOT the same number.


If Penrose’s work helped calculate voting power under a system of weighted voting (as my Banzhaf Index does), it certainly was not well known.

As evidence, note that many counties in New York used it until I was able to have it declared unconstitutional based upon the Banzhaf Index.

PS: Although Joe says "Clearly you have to dedicate the next book to him instead," this can't be true since I have never written a book.

Posted by: LawProf John Banzhaf | Jun 16, 2021 5:34:55 PM

"...today it’s widely known as the “Banzhaf Index of Voting Power” ..." In fact it is usually known as the Penrose-Banzhaf measure, Penrose being the first one to advance it, in the 1940s.

Posted by: Hugh | Jun 16, 2021 4:11:16 PM

Clearly you have to dedicate the next book to him instead.

Posted by: Joe | Jun 15, 2021 6:13:37 PM

I knew him as Professor Jack Weinstein when I was a student at Columbia Law School from 1962-1965.

He inspired me to write my first law review article [Banzhaf, Weighted Voting Doesn't Work: A Mathematical Analysis, 19 Rutgers L. Rev. 317 (1964-1965)] - when I was still a law student - although that’s almost certainly not what he intended.

Here’s what happened.

As a second-year law student, I had just joined the Law Review. Weinstein had just submitted an article for publication about the Supreme Court’s “One Man, One Vote” decision.

In it he suggested that, if new district lines could not be drawn so that the populations of each voting district were somewhat close to equal as the law now required, one could use “weighed voting.”

For example, if one voting district had about three times as many people as the other districts, and could not easily be divided into three equal-population districts, simply give the legislator from that district three votes instead of one.

Because I was the only one on the Review who had any mathematical training (as an MIT graduate), I was asked whether that would work. My immediate answer was “of course not.”

So I was ordered to go to law school office of “Big Black Jack,” as he was then known, and tell him. When I did, he did not take it very well.

In fact he stood up and, towering over my 6ft 200 pound figure, shouted: “if you are so God damned smart, write your own law review article.”

So I did!

To prove that he was wrong, I had to invent a new mathematical measure of voting power - today it’s widely known as the “Banzhaf Index of Voting Power” - and it’s taught in most colleges and even many high school math courses.

I used the article to have weighted voting declared unconstitutional [Iannucci v. Board of Supervisors, 229 N.E. 2d 195 (1967)].

Subsequently I used the Banzhaf Voting Power Index to prove that, contrary to conventional wisdom, it was people in the most populous states who had the most voting power [Banzhaf, 3.312 Votes, A Mathematical Analysis of the Electoral College, 13 Villanova L. Rev. 303 (1968)], and to analyze many other voting systems.

I greatly admired Prof. Weinstein, and certainly would not fault him for not seeing the mathematical problems with weighted voting - something other politicians and mathematicians also hadn’t recognized.

Indeed, during the many years that Nassau County (Long Island, NY) used weighed voting, nobody realized that half of the supervisors had no voting power at all.

My professor, of course, went only to become a famous and trail-breaking judge, and I will always be grateful to the nudge he gave me, and happy that he was able to make so much new law while on the bench.

Posted by: LawProf John Banzhaf | Jun 15, 2021 5:44:56 PM

I too got a handwritten note when I commented on Geoffrey Hazard's review in the Yale Law Journal of the judge's book on U.S.Supreme Court and lower federal court rulemaking (based on an Ohio State law Review article). Still have it.

Posted by: Jeffrey A. Parness | Jun 15, 2021 4:55:45 PM

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