When Sheldon Adelson first donated $5 million to a pro-Newt Gingrich Super PAC, he enabled the candidate to compete effectively with Mitt Romney. After learning this week that Adelson’s wife has donated another $5 million, Chris Hayes observed that Newt Gingrich will have a “direct and personal debt” to the billionaire, should he be elected president. In this episode of Up with Chris Hayes, he asks: Who is Sheldon Adelson, anyway?

In the same episode, Nation editor Richard Kim, Representative Carolyn Maloney (D-NY), Demos’s Heather McGee, Manhattan Institute fellow and National Review Online contributor Josh Barro and Pulitzer Prize–winning reporter David Cay Johnson address the ongoing tax policy debate and Mitt Romney’s tax returns.

—Erin Schikowski