Nice analogy in The Atlantic on the campaign finance zeal of the “reformers”:

Campaign-finance reform is a bit like the war on drugs: a decades-long
exercise in over-regulation that has exacerbated the problems it was
designed to solve.

And a good breakdown of the actual issue the Supreme Court will review:

It’s important to stress that McCutcheon is not challenging limits on
individual or base contributions to party committees or individual
candidates. (Candidate contribution caps were $2,500 per federal
election in 2011-2012; contributions to national party committees were
capped at $30,800 per year.) He is challenging aggregate limits on
contributions to candidates and parties. In other words, he is not
demanding a right to give more than $2,500 to any candidate; he’s
demanding a right to give as much as $2,500 to more candidates, in
excess of the aggregate cap.