Today, the IRS official at the heart of the investigation into the targeting of Tea Party groups appeared before a House Committee and took the Fifth.

NPR: With White House Bogged Down By Scandal, GOP Looks For Boost

The official, Lois Lerner, said that agency workers picked groups for extra scrutiny according to whether they had "tea party" or "patriot" in their names, among other criteria.

WSJ: IRS Scrutiny Was Deeper Than Thought