Internal Revenue Service Commissioner John Koskinen needs to go.

When it was revealed in 2013 that the IRS had targeted conservative groups for exercising their First Amendment rights, President Obama correctly called the policy “inexcusable” and pledged accountability. He even fired the then-acting IRS commissioner because he said it was necessary to have “new leadership that can help restore confidence going forward.”

Unfortunately, Commissioner Koskinen, who took over in the wake of the IRS targeting scandal, has failed the American people by frustrating Congress’s attempts to ascertain the truth. A taxpayer would never get away with treating an IRS audit the way that IRS officials have treated the congressional investigation. Civil officers like Mr. Koskinen have historically been held to a higher standard than private citizens because they have fiduciary obligations to the public.