A Guide to the IRS Scandal—What Happened and When Did It Happen?

Revelations that the Internal Revenue Service targeted conservative groups have put the Obama White House on the defensive and are raising serious questions about what officials knew, and when they knew it. 

Among the new details that have come out: At least one official at the IRS knew in 2011 about the efforts to single out conservative groups who applied for tax-exempt status. The White House counsel knew about the IRS story during the week of April 22, more than two weeks before the president said he found out about it, press secretary Jay Carney said Monday. And Senate Republicans and Democrats engaged in a tug-of-war over whether the IRS was unfairly targeting conservative groups throughout 2012. 

The drip-drip of news since the story broke on Friday when the IRS' Lois Lerner admitted the agency targeted conservative groups, only underscores the high political stakes for the White House. 

The IRS scandal and fresh questions about Obama's handling of the Benghazi attacks have set the White House on its heels. The next mile marker will likely be the release of the full inspector general's report that was leaked over the weekend and that detailed how far back the IRS' knowledge of the targeting extended. Until then, orient yourself with National Journal's timeline.

Click here to view the timeline.