Senate Democrats have rolled out this year's model of the DISCLOSE Act. Or, if you want to be more formal: the Democracy Is Strengthened by Casting Light on Spending in Elections Act.

It's the third version of DISCLOSE since 2010. Broadly speaking, it would force donor disclosure on the big-money, 501(c)(4) social welfare organizations that are flourishing in post-Citizens United politics. Unlike almost all other players in an election campaign, 501(c)(4)s are not covered by the disclosure laws. Their donors are never publicly named.