While Washington politicians are lining up to denounce the IRS targeting of Tea Party groups, U.S. Sen. Al Franken entertained a question from CNN's Jake Tapper Monday about whether some political groups aren't in fact masquerading as non-profits. "This is the issue," the Minnesota Democrat said, "it just should be done in a completely non-partisan way." Franken, a critic of the Supreme Court's Citizen United decision that loosened restrictions on money in politics, weighed-in on the IRS controversy at the end of an interview about Wall Street reform. In a rare national TV appearance, Franken said "These 501(c)(4)'s [non-profits], in order to be tax-exempt, in order for people to give them money and also not be disclosed who they are, the 501(c)(4) has to spend at least 50 percent, plus a dollar, on actual social welfare. "So, some of these organizations have been, you know, it looks like they have been spending more on just pure politics. So it's a legitimate inquiry by the IRS. What is in no way legitimate is that this be biased in any way. And the people responsible for this should be held accountable."