The Attorney General of the United States told a Senate subcommittee today that the federal government spied on a U.S. political campaign in 2016. Now Americans need to know which executive branch officials were responsible for turning Washington’s formidable surveillance powers against the party out of power.

The Journal reports:

Attorney General

will ask a team inside the Justice Department to examine the origins of the counterintelligence investigation into the Trump campaign’s possible ties to Russia, he told Congress on Wednesday, responding to lingering Republican concerns about law enforcement decisions during the 2016 election.

Mr. Barr characterized the law-enforcement activities that were directed at people affiliated with the Trump campaign as “spying,” telling a Senate panel that he will examine the gamut of intelligence activities that were directed at members of the campaign in 2016, looking at how and why surveillance decisions were made.

“I think spying on a political campaign is a big deal,” Mr. Barr said in a hearing, invoking Vietnam-era intelligence abuses, such as the surveillance of antiwar activists as a reason to raise these questions. “Spying did occur. The question is whether it was adequately predicated.”

William Barr

It is a big deal, even if much of the press corps runs every development in this story through the filter of whether it is good news or bad news for Donald Trump. It is unconditionally bad news for the citizens of a free society if it becomes acceptable for the government to spy on domestic political opponents.

“I feel I have an obligation to make sure that government power is not abused. I mean I think that’s one of the principal roles of the attorney general,” Mr. Barr added. Indeed it is.

The Attorney General also did a public service in implicitly reminding lawmakers that they too have a responsibility to protect our liberties. Said Mr. Barr: