Fast and Furious
Gunrwalking scandal with a side of perjury and obstruction. This was where BATF under Eric Holder was selling guns to Mexican drug cartels, failing to track them, and some Americans (including Brian Terry) were shot with said guns. The likely reason for doing this, was to encourage the narrative the administration had invented that Mexico's gun problems were because of the U.S., and the solution was more fascism (gun control in the U.S.). In truth it showed the corruption of the Obama Administration, as well as the incompetence in failing to track them. Republicans wanted an investigation, but "the most transparent administration ever" obstructed justice and gave Holder "executive privilege" to prevent the transparency he'd promised. They also lied and said this was a follow on to a much smaller 2007 effort during the Bush administration (called Wide Receiver): which had been done without President or Cabinet involvement, and had been shut down with the recommendation to never try anything this stupid again (which the Obama administration had ignored).