If special counsel Bob Mueller is truly interested in investigating people who are colluding with nefarious foreign powers to undermine U.S. interests, John Kerry should be Target No. 1 for secretly meeting with Iran’s foreign minister, Javad Zarif, and other foreign officials in recent weeks to usurp U.S foreign policy.

It’s a role that as a private citizen, Kerry has no mandate or authority to pursue.

The Boston Globe reported Friday that Kerry has been engaging in stealth diplomacy, secretly meeting with high-ranking officials including in Germany, France and the Islamic State to salvage the contentious Iran nuclear deal he orchestrated during the Obama administration.

Why isn’t the DOJ raiding Kerry’s manse, as it did with Trump’s attorney Michael Cohen?

Or putting the former secretary of state under house arrest, as it did with former Trump campaign manager Paul Manafort?

It’s no secret Iran, the world’s leading sponsor of terror, openly chants “Death to America” and “Death to Israel” while using millions in unmarked currency Kerry and Obama administration officials secretly sent unbeknownst to the American people. That money is reportedly being used to fund terror proxies, including Hezbollah and Hamas.

Kerry has now been caught meddling in U.S. foreign policy and conspiring with foreign nations to prop up the collapsing Iran nuclear deal — a textbook violation of the Logan Act. Yet the Department of Justice went after former national security adviser Gen. Michael Flynn with a vengeance for contacts with a Russian diplomat during the 2016 transition despite it not being illegal to do so. Obama’s FBI then set perjury traps against Flynn and have destroyed his life as a result.

But John Kerry is a free man, providing additional evidence — if you needed any — our justice system has become dangerously politicized.

Perhaps the Democratic Party, Attorney General Jeff Sessions and FBI Director Christopher Wray can explain how it’s OK that Kerry has colluded with foreign actors while the Mueller team and Justice Department continue to engage in a scorched-earth campaign against the Trump administration over faux Russian collusion theories that haven’t borne fruit despite a string of costly government investigations.

What other Deep State officials have been working with Kerry to sabotage U.S. foreign interests? Barack Obama? Former White House officials and swamp-dwellers within the government?

Congress must open an investigation to find out.

A failure to do so will reveal just how partisan and corrupt the Department of Justice has become.

Adriana Cohen is a columnist for the Boston Herald, radio host and syndicated columnist. Follow her on Twitter @AdrianaCohen16.