It is not enough that Jeff Sessions stepped aside Thursday.

What matters now is that an independent special prosecutor is appointed, one above all partisanship, who is determined to chase down every lead into any and all secret dealings between Russia, Donald Trump and the Trump presidential campaign.

Who in the Trump camp was involved? What exactly are Trump’s past and present business ties to Russia and influential individual Russians? What are his staff and advisers’ ties? What foreign policy understandings may have been reached with a wink and nod? What promises might have been made? Who else knows exactly what?

EDITORIAL

The stakes are far too high for this investigation to be left to Attorney General Sessions’ deputy or to the Justice Department as a whole, which Sessions will continue to head. And a select committee of Congress would be ill-equipped to take the broadest possible approach.

Only a special prosecutor, enthusiastically endorsed by Congress on both sides of the aisle, will suffice. This investigation must go wherever the truth leads, without reservation.

On Thursday, Sessions removed himself from any investigation amid furor over the revelation that he, during his Senate confirmation hearing, failed to disclose under questioning that he twice had met with the Russian ambassador last year. Sessions’ own actions, including whether he purposely misled the Senate committee, now become part of the federal inquiry.

In ordinary circumstances, Sessions’ recusal would mean the job of investigating Trump’s ties to Russia — and Russia’s tampering in the election — would be turned over to the acting deputy attorney general, Dana Boente, or to the man soon likely to replace Boente as deputy, Rod Rosenstein, pending confirmation by the Senate.

But Boente would be suspect. He was Trump’s choice to replace Obama administration hold-over Sally Yates, whom Trump fired for refusing to enforce his travel ban. Rosenstein, the U.S. attorney for Maryland, also would be suspect, having been nominated by the president.

The only trustworthy way forward is for Boente or Rosenstein to name a special prosecutor of unimpeachable integrity and deep experience — somebody Congress across the board can support. Strictly Republican appointees need not apply.

The heart of the matter is the question of whether an unfriendly foreign power attempted to tilt an American presidential election. As long ago as October, two agencies — the Department of Homeland Security and the Office of the Director of National Intelligence — said the U.S. intelligence community had concluded that Russia was behind a hacking operation to interfere with the presidential elections. The unanimous view of government intelligence agencies, including the CIA and the FBI, is that the Russian government directed cyber attacks against U.S. political organizations. CNN has reported that multiple sources say high-level Trump associates were in constant contact with Russians who were known to U.S. intelligence.

Yet here we are in March, with no answers. We can’t even say we know all the questions.

Federal investigators have been looking into contacts between Trump advisers and Russia for months. House and Senate intelligence committees are conducting separate investigations. But to say the congressional probes are running at a snail’s pace is unfair to snails.

As for the Trump White House, it is once again in nothing-to-see-here mode, insisting this week that questions about Sessions’ meetings with the Russian ambassador are nothing more than “the latest attack against the Trump administration by partisan Democrats.” This is an administration with serious messaging issues. Just hours before Sessions announced he would recuse himself, Trump said he did not think his attorney general needed to do so.

In choosing a special prosecutor, we urge the Justice Department and Congress to heed the example of Patrick Fitzgerald, the former U.S. attorney for Northern Illinois, who in 2003 led a strong investigation into a government leak of the name of a CIA operative, Valerie Plame. Fitzgerald’s work, at a time when Republican George W. Bush sat in the White House, led to the conviction of Vice President Dick Cheney’s chief of staff, Lewis “Scooter” Libby.

Jeff Sessions did the right thing by recusing himself. Whether he might now be compelled to resign remains an open question.

The more pressing matter is to appoint a superb special prosecutor who gives no quarter.

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