Things can’t get much worse for John McCain. Just last night I wrote about his plummeting poll numbers and speculation he might drop out of the presidential race. Now he’s faced with another setback. The Supreme Court this morning struck down a key provision of the campaign-finance law that bears McCain’s name. Romney, seizing on the opportunity, quickly fired off this statement:

Score one for free speech. Today the Supreme Court reaffirmed the First Amendment by rejecting a key feature of McCain-Feingold. The law trampled the basic right of the American people to participate in their democracy. It also purported to reduce the influence of money in politics, but we now know that influence is greater than ever. McCain-Feingold was a poorly-crafted bill. Today’s decision restores, in part, to the American people a right critical to their freedom of political participation and expression.

The campaign-finance ruling was one of several issued by the court today. Get more coverage at SCOTUSblog and How Appealing.

UPDATE — 12:55 p.m.: Senate Minority Leader Mitch McConnell (R.-Ky.), who strongly opposed campaign-finance reform, released a statement hailing the court’s decision.

Americans have a constitutionally protected right to hold their elected representatives accountable and, I hope, with this important decision, we can begin to undo the stranglehold that campaign finance legislation has placed on political debate.

So far, the bill’s two authors, Senators McCain and Russ Feingold, haven’t said a peep on their websites.