  In recent years, enlargement of the European Union has led to increased
interest in the allocation of voting weights to member states with hugely
differing population numbers. While the eventually agreed voting scheme lacks
any strict mathematical basis, the Polish government suggested a voting scheme
based on the Penrose definition of voting power, leading to an allocation of
voting weights proportional to the square root of the population (the
"Jagiellonian Compromise"). The Penrose definition of voting power is derived
from the citizens' freedom to vote either "yes" or "no". This paper defines a
corresponding voting power based on "yes", "no" and "abstain" options, and it
is found that this definition also leads to a square root law, and to the same
optimal vote allocation as the Penrose scheme.
