Yes, the four justices that dissented had arguments too, but I personally think one needs to stretch quite far to find McCain-Feingold constitutional. The text of the decision (including dissents) at <a href="http://www.supremecourtus.gov/opinions/09pdf/08-205.pdf" rel="nofollow">http://www.supremecourtus.gov/opinions/09pdf/08-205.pdf</a> gives all the arguments, and is very informative. (But reading it in full would probably be a waste of time...)