After the Supreme Court’s decision in Citizens United v Federal Election Commission, which gave corporations unlimited rights to spend money to influence elections, I am leaning in favor of a constitutional amendment to permit the regulation of campaign finances. The need will be even more pressing if the Court overturns Arizona’s system of public funding for candidates, as appears likely.

But it will not be easy to get the amendment right (even imagining that it can pass). Although spending should not be equated with free speech, regulating campaign spending does raise genuine First Amendment issues. Unchecked by courts, Congress could deliberately set the spending limit so low that incumbents would be safe. Or worse, it could ban some groups from spending while setting no limits on others. That is why the Supreme Court should have approved reasonable campaign finance laws (applying First Amendment scrutiny) and allowed us to leave the Constitution alone.

If we must amend the Constitution, I’m not sure I favor the leading proposal, which says: “Congress shall have power to set limits on the amount of contributions that may be accepted by, and the amount of expenditures that may be made by, in support of, or in opposition to, a candidate for nomination for election to, or for election to, Federal office.” (It also grants similar powers to state legislatures and gives Congress the right to enforce the limits.)

Would this text allow Congress to set a spending limit of $1 and prohibit any advertising? (Given incumbents’ ability to send free mailings and obtain free news coverage, they have incentives to set low limits.) Would this text permit Congress to ban newspapers from running articles “in support of” candidates? Perhaps a court would balance the new amendment with the First Amendment, but I am not sure that the plain text cited above would allow such balancing.

I lack the expertise and experience to write a better amendment, but I think it would have to invoke such principles as fairness to challengers and reasonable access to communications media, so that courts could strike down inappropriate limits. Ultimately, I am less enthusiastic about limits than about public funding for campaigns–which is fully constitutional until the Supreme Court says otherwise.