But if President Obama had refused to join in this downward spiral — and if he had proudly campaigned on that refusal — he and his campaign might have made up for that deficit in other ways: with more small contributions, and more support, from a public disgusted by the outsize influence of big money.

A president has a megaphone bigger even than Mr. Rove’s bloated bank account, and Mr. Obama could have impressed many wavering voters if he had chosen to use it against campaign corruption. He could have pointed out that it was Republicans who blocked the Disclose Act, which would have ended secret corporate donations, and that it was Republicans who used unlimited corporate funds to win back the House in 2010, pressing a corporate agenda that has severely hurt the middle class…

But now Mr. Obama has given up that higher ground. He had already undermined the public financing system for presidential campaigns by refusing to use it in 2008, but this is much worse. In that campaign, he at least forswore money from independent groups and lobbyists. Now he is relying on a super PAC that can accept money from anyone.