Posner is clearly correct that the analytical differences between “super Pacs” and direct campaign contributions to candidates are not large enough to justify disparate treatments. Yet, because they should be treated the same way does not necessarily imply that spending by super Pacs should also be sharply controlled. I believe that it is very likely preferable to apply the reasoning in Citizens United v. Federal Election Commission to direct contributions than to extend the limits on direct contribution to super Pacs.
I agree with Posner that candidates with political positions attractive to rich individuals may obtain considerable funds that give these candidates political advantages in appealing to voters. Such political contributions may well also affect the policies supported by candidates and elected officials. This is the corruption issue raised by Posner and by much of the literature that supports sharply limiting campaign contributions.
Sharp restrictions on campaign contributions would make more sense if monetary contributions were the only major force that shapes who wins elections and the policies goverment officials support.Yet that is very far from the situation that prevails in American politics, and in the politics of most other democratic nations. One reason for this is that interest groups can often avoid the intent of restrictions on campaign contributions through other ways to influence political outcomes. For example, many industries hire lobbyists and spend other monies to try to persuade legislators, regulators, and others in important political positions to subsidize their industries, or to reduce the taxes on their industries, or to gain other advantages.