Are you a rich guy being investigated for potential criminal prosecution? No worries! Exercise your free speech rights by dumping millions of dollars of corporate money at your control into a PAC to challenge the prosecutor's re-election bid. The new prosecutor, beholden to you for his job, is sure to lose interest in that prosecution.
Is this what Justice Kennedy anticipated when he opined, "The [government's] anticorruption interest is not sufficient to displace the speech here in question."