Darrell Issa is about to reach a regrettable milestone.

The California Republican is one summons away from issuing his 100th subpoena since becoming chairman of the House Oversight and Government Reform committee in 2011 – all of them without a committee vote and the vast majority without the concurrence of the committee’s ranking Democrat.

The “unilateral subpoenas,” as they are known, are a departure from the way the committee has conducted its investigations for decades and an echo of the late Clinton years, when conspiracy-minded Chairman Dan Burton fired off more than 1,000 subpoenas.

The careless use of the subpoena – the power to compel a witness’ appearance or the production of documents – has discredited Issa’s chairmanship by politicizing his probes from the start. His unilateral style has also been a leading contributor to the overall toxicity in politics by turning his committee into a forum for partisan clashes over Benghazi, Libya, the Internal Revenue Service and Eric Holder’s Justice Department.

Recently, senior White House official David Simas has been ordered by Issa, under a unilateral subpoena, to testify about political activities Issa alleged are illegal. Issa has issued two unilateral subpoenas to compel the testimony of Secretary of State John Kerry over Benghazi, and another subpoena to force the testimony of the IRS commissioner (even though the official had offered to testify).

Though it has long bestowed unilateral subpoena power on the chairman, the committee didn’t issue a single unilateral subpoena from the 1950s until the mid-1990s, according to Phil Schiliro, who served as the committee’s Democratic staff director for a decade beginning in 1997.

In the eight years after Burton’s chairmanship, virtually all of the 78 subpoenas issued (under Republican Chairman Tom Davis and Democratic Chairmen Henry Waxman and Edolphus Towns) were done either with the minority’s consent or with a committee vote. Davis and Waxman managed to cooperate even on highly charged matters such as the Jack Abramoff and Pat Tillman investigations.

Schiliro said that 43 of Waxman’s 46 subpoenas were issued with Davis’ consent, and the other three were put to a vote. The act of justifying a subpoena to the committee “forces collaboration,” he said, and “goes to whether there is a legitimate investigation or not.”

Issa’s deputy staff director, Frederick Hill said that Issa – unlike his immediate predecessor, Towns – consults with the minority before each subpoena.

Without the minority’s sign-off and without even a public debate on the merits of a subpoena, the unilateral subpoena is a way to float allegations in lieu of investigative work. This generates complaints about “fishing expeditions” from those who receive the subpoenas – and counter accusations of “cover-ups” when an administration resists.

Issa’s Benghazi probe has been typical of this approach. He used his subpoena with a heavy hand: He ordered Ambassador Thomas Pickering, who led an administration probe into the Benghazi attacks, to submit to a private interview, even though Pickering had volunteered to testify publicly.

Issa coupled that with unfounded allegations, declaring his “suspicions” that then-Secretary of State Hillary Clinton told the Pentagon to “stand down” rather than help Americans in Benghazi. Likewise, Rep. Jason Chaffetz, R-Utah, who is vying to succeed Issa as chairman next year, said he found it “disgusting” that a special operations team was “told to stand down” rather than assist in Benghazi.

But declassified testimony released last week by the House Armed Services Committee disproved such allegations. Military officials up and down the chain of command testified – voluntarily – that they received rapid approval to mobilize assets during the attack and that two quick-reaction teams had been alerted for deployment. The head of a four-man team in Tripoli that was allegedly told to stand down testified that he received no such order and that his orders to remain in Tripoli rather than fly to Benghazi were “instrumental” in saving the life of a wounded American.

Armed Services Chairman Rep. Howard “Buck” Mc- Keon, R-Calif., whose committee conducted a more responsible Benghazi investigation than Issa’s, says he’s “pretty well been satisfied that … we probably couldn’t have done more than we did.”

The testimony should satisfy Issa, too – if his real purpose is to answer questions and not to issue subpoenas.

Dana Milbank is a columnist for The Washington Post. He can be contacted at:

danamilbank@washpost.com