House Democrats have declared all-out war on Rep. Darrell Issa, R-Calif., chairman of the House Oversight Committee and leader of aggressive investigations of the Obama administration's failure to provide adequate security for the U.S. mission in Benghazi and the Internal Revenue Service's crackdown on conservative groups. They charge him with partisan recklessness and failing to follow the rules.

Contrary to those assertions, Rep. Issa has uncovered damning evidence on Benghazi and appears to have taken the proper steps to file contempt proceedings against the person at the heart of the IRS scandal, retired career civil servant Lois Lerner.

Last week, the top lawyers for the House of Representatives concluded that Rep. Issa had not violated "the prerequisites required by the Supreme Court in order to hold a witness in contempt."

A memorandum from the general counsel of the House agreed that it is still possible to bring charges of contempt against Ms. Lerner for asserting a faulty Fifth Amendment refusal to respond under oath to committee questions.

The legal memorandum said Ms. Lerner had waived her right to the Constitution's protection against self-incrimination when she testified last year:

"I have not done anything wrong. I have not broken any laws. I have not violated any IRS rules or regulations. And I have not provided false information to this or any other congressional committee."

The memo also said the committee had given her fair warning that invoking the Fifth Amendment and refusing to answer its questions exposed her to a contempt citation.

Rep. Elijah Cummings of Maryland, the ranking Democrat on the committee, insists that his chairman and the House general counsel got it wrong on the contempt question.

A federal judge ultimately might have to settle the issue.

But there's one way to start the ball rolling: Seek a contempt citation.

There's compelling evidence that instructions to politicize the IRS process of authorizing tax breaks to non-profit groups came from the Washington office headed by Ms. Lerner.

She shouldn't be allowed to stonewall Congress without consequences.