1. Cohen versus nozick: Argument #1
A just distribution arises from another just distribution by voluntary transactions only if the people affected by the transactions are made better off after the fact.
Giving Wilt Chamberlain money can create inequality, the consciousness of which makes his customers worse off after the fact.
∴ Giving Wilt Chamberlain money may create an unjust distribution.

2. Cohen versus nozick: argument #2
Assume for sake of argument violating side constraints is wrong.
Something wrong ought to be minimized.
∴ Violating side constraints ought to be minimized.
But side constraints prevent minimization of side constraints violation.
∴ Side constraints are irrational: they both require and forbid minimization of their violation.

3. Cohen versus nozick: argument #3
A reduction of options is a reduction of liberty. (Stipulate.)
Exercises of negative liberty can reduce others’ options.
∴ Exercises of negative liberty can reduce liberty.
We should maximize liberty (not necessarily to the exclusion of other goals – perhaps as part of some social welfare function).
∴ We should restrict some exercises of negative liberty.