The IRS targeting and muzzling of conservative groups during the 2012 presidential campaign is an outrage for which almost no one has been held accountable. Which brings us to the news that House Oversight Committee Chairman Jason Chaffetz introduced articles of impeachment on Tuesday against IRS Commissioner John Koskinen.
Mr. Koskinen was not at the IRS during the targeting, but the former Freddie Mac executive has become the single greatest hurdle to public accountability. He was touted as a reformer in his 2013...