Although the critics of Citizens United might well be right to condemn it and to call for a constitutional amendment to overrule it, they are misguided in their reliance on the refrain that "money is not speech." Of course, money is not "speech." Money is money, a car is a car, and a ribbon is a ribbon. These are objects, not speech. But all of these objects, and many more besides, can be used to facilitate free speech.
Like a car or a ribbon, money is not speech. But when government regulates the use of money for speech purposes, it implicates the First Amendment. Suppose, for example, an individual at an Occupy protest burns a dollar bill to convey her disdain for corporate America. A dollar bill is not speech, fire is not speech, but a government law prohbiting any person to burn money as a symbolic expression of opposition to corporate America would surely implicate the First Amendment.
This is not to say, however, that the government cannot constitutionally regulate the use of money in politics. The fact that an object is used to facilitate speech does not mean that it is immune from regulation. The use of a loudspeaker is speech, but the government can regulate the decibel level. Burning a dollar bill for expressive purposes is speech, but the government can prohibit anyone from doing so near an open gas line. And the same is true for campaign contributions and expenditures. When the government attempts to regulate the use of money for expressive purposes it implicates the First Amendment, but it does not necessarily violate it.
If the critics of Citizens United and the advocates of a constitutional amendment to overrule it want to be taken seriously, they must move beyond superficial slogans and focus on the real issue at stake: When should the government be allowed to regulate political contributions and expenditures — even if they are speech?