01/18/2012 03:58 pm ET Updated Jan 18, 2012

David Shuster Calls Out Campaign Finance As 'Cancer That Threatens Our Democracy' (VIDEO)

David Shuster blasted the flood of corporate money into GOP candidates' campaigns, and called on viewers to stop it on Tuesday.

Filling in for Keith Olbermann on "Countdown," Shuster lamented the Supreme Court's Citizens United ruling, which allows organizations to make unlimited political donations. The host noted that campaign spending is expected to reach $8 billion this year. "It is increasingly clear that growing corruption in our campaign system is a cancer that threatens our democracy," he said.

Then, Shuster turned his attention to Amend 2012, a new initiative to pass a constitutional amendment reversing the Citizens United ruling. The resolution has already been unveiled in Vermont. He implored viewers to take action to reverse Citizens United, whether by supporting the initiative or through other means. Watch his passionate monologue in the clip above.