When the new Republican-led Congress convenes in January, unraveling the Benghazi scandal should be a top priority.

The House Select Committee on Benghazi started its work this summer. Soon the Senate will be in position to contribute.

Sen. Ron Johnson, R-Wis., one of the most vocal critics of former Secretary of State Hillary Clinton and her role in the Benghazi debacle that cost four Americans their lives, will be the next chairman of the Senate Oversight Committee on Governmental Affairs. In this role, he will have the power to issue subpoenas to government officials.

Some of the weaknesses of the previous Senate hearings on Benghazi have included posturing by committee members and a lack of follow-up questions to uncover information withheld by administration officials. But Johnson, who was elected to the Senate in 2010, proved himself unintimidated by Hillary Clinton’s aggressive posturing during Senate Intelligence Committee hearings on January 23, 2011, which suggests he will be adept at handling hearings well.

Talking to Clinton in the 2011 hearing, Johnson zoomed in on the Obama administration’s apparent attempt to mislead the victims’ families and the American public. He demanded to know why no one at State or the White House tried to get an answer from individuals on the ground in Benghazi before letting then-UN Ambassador Susan Rice serve up a misleading version of events on five Sunday talk shows. (Of course, we know now that the CIA actually had information from its Tripoli station chief that contradicted the talking points.) Johnson said:

What I mean that is that a very simple phone call to these individuals would have ascertained immediately that there was no demonstration. This attack started at 9:40 p.m. Benghazi time. It was an assault. . . .I am going back to the fact that Ambassador Rice was going on the Sunday talk shows and purposely misleading the American people.  I appreciate the fact that we are transparent at this hearing, but why were we not transparent at that point in time?

Hillary Clinton tap-danced around the question. But after being pressed twice by Johnson because of her evasiveness, she finally blew up. “The fact is that we had four dead Americans, and if it was because of a protest or because there were four guys out taking a walk and deciding to kill some Americans, at this point, what difference does it make?” she famously shouted.

What difference? A lot. This is particularly so as it was Clinton herself who signed the order to downgrade security for U.S. diplomats in Benghazi, despite ample and repeated warnings about the rising terrorist threat in Benghazi. In the Wall Street Journal last year, Johnson wrote about Clinton’s attempts to use the Accountability Review Board’s report to shield herself from responsibility:

Yet a April 19, 2012, State Department cable responding to former Ambassador Gene Cretz’s request for additional security in Benghazi bears Mrs. Clinton’s signature. That cable specifically acknowledges Mr. Cretz’s request for additional security, and “stipulates that the plan to draw down security assets will proceed.”

Johnson concludes the op-ed with a point that the incoming leadership of the Senate should take under advisement: “A congressional Joint Select Committee can offer that protection [for the whistleblowers] and issue those subpoenas. Such a Committee should be appointed without further delay.”

The Government Oversight Committee of the Senate will be a powerful tool, but even more powerful would be for the Senate to team up with the work of the House Select Committee on Benghazi.