Judicial Modesty and Campaign Finance Reform

In the run-up to last week's rehearing of the campaign finance reform case Citizens United v. FEC, a number of prominent liberal commentators argued that only a shamelessly "activist" Supreme Court would dare overturn its own campaign finance precedents. This weekend, George Washington University law professor Jeffrey Rosen added his voice to the chorus, focusing on Chief Justice John Roberts' famous preference for "judicial modesty." As Rosen wrote in The New York Times:

Many conservatives, and even some liberal devotees of the First Amendment, are urging the Roberts court to uproot federal and state regulations on corporate campaign spending that date back to 1907, as well as decades of Supreme Court precedents. If Chief Justice Roberts takes that road, his paeans to judicial modesty and unanimity would appear hollow.

I'm not a big fan of judicial restraint and I'm certainly not interested in defending Roberts' "paeans to judicial modesty," but what's so special about laws "that date back to 1907"? I'm pretty sure the First Amendment has been around longer than that. Besides, bad precedent can and should be overturned.