Darrell Issa, the chairman of the House Oversight and Government Reform Committee, says he is confident the story behind the IRS’s targeting of tea-party and conservative groups applying for tax-exempt status will eventually come out. But patience will have to be a virtue. Issa’s staff acknowledged late last month that the IRS had handed over to the committee a little more than 10 percent of the documents the IRS itself has admitted are relevant to the committee’s investigation. Issa mentioned the case of “Susanne,” a lawyer whom he said had worked for Democrats on the House Oversight Committee until 2008....