Rep. Adam B. Schiff, the chair of the House Intelligence Committee, speaks to reporters at the U.S. Capitol on Feb. 28. (Jahi Chikwendiu/The Washington Post)

John Yoo, a law professor at the University of California at Berkeley, served as general counsel of the Senate Judiciary Committee from 1995 to 1996 and is a visiting fellow at the American Enterprise Institute and the Hoover Institution.

It’s impeachment or bust. That’s the message sent by special counsel Robert S. Mueller III to critics of President Trump. In his release of the Mueller report Thursday, Attorney General William P. Barr only underscored this lesson by finding that the evidence does not support charging the president with obstruction of justice. Whether you agree on the criminal law, it is the right result on the separation of powers. The Constitution itself establishes impeachment, not prosecution, as the answer to a corrupt sitting president.

After an expensive, damaging two-year inquiry, Mueller has done Trump a great favor by definitively clearing the president, his campaign and his administration of conspiring with Russia to break federal law. Mueller found significant Russian efforts to influence the elections and to harm Hillary Clinton’s candidacy, but he found no cooperation by the obvious beneficiary, the Trump campaign.

But Mueller ominously refused to reach the same conclusion on presidential obstruction of justice, on which he pointedly says the evidence does not exonerate Trump. Both Mueller and Barr properly agreed that Justice Department legal opinions prohibit them from indicting a sitting president. As the Office of Legal Counsel concluded in 2000, such an act “would impermissibly undermine the capacity of the executive branch to perform its constitutionally assigned functions.”

Mueller, however, did not stop there. He identified 10 separate episodes that could have amounted to obstruction. These events did not take the form of traditional interference, such as destroying evidence or threatening witnesses. Instead, they took far more subtle forms, such as Trump’s firing of FBI Director James B. Comey, his order to White House counsel Donald McGahn to remove Mueller, and his order to Attorney General Jeff Sessions to rein in the investigation. These could have impeded the probe but also could have represented the president’s good-faith exercise of his constitutional authority over law enforcement.

The Mueller report, and Barr’s declination to prosecute, do not end the matter. Mueller observed that the Justice Department does not prosecute sitting presidents so as not to “potentially preempt constitutional processes for addressing presidential misconduct.” He can be referring only to impeachment. He took pains to note that, even though he could not prosecute, his office “conducted a thorough factual investigation in order to preserve the evidence when memories were fresh and documentary materials were available.”

Mueller, in other words, tacitly invited Congress to use his report as a jumping-off point for its own investigation. If Trump has truly obstructed justice, Congress could begin by blocking White House legislative proposals, budgets and nominees. Congress could next turn to impeachment, which allows for the removal of a president for “high Crimes and Misdemeanors.”

Impeachment does not require the president to commit a crime, but instead refers to significant political mistakes or offenses. As Alexander Hamilton observed, they “are of a nature which may with peculiar propriety be denominated political, as they relate chiefly to injuries done immediately to the society itself.” After the Civil War, for example, the House impeached, and the Senate came within one vote of removing, President Andrew Johnson for attempting to end Reconstruction prematurely. Congress can examine the same conduct as Barr but conclude that it warrants Trump’s removal from office even if it does not violate criminal law.

From a constitutional perspective, we should welcome the Mueller report and the Barr declination. Ever since Watergate, our political system has run a wayward experiment to use special counsels and criminal law to restrain presidential wrongdoing. Independent prosecutors diverted executive power outside constitutional controls and sapped the presidency of its energy. Frequently, Justice Antonin Scalia famously wrote, an effort to undermine the Constitution’s separation of powers “will come before the Court clad, so to speak, in sheep’s clothing.” But in a case upholding the independent counsel , he warned in dissent, “this wolf comes as a wolf.”

A special counsel such as Mueller may be a slightly different and less constitutionally offensive creature, but it bears the same faults. We can also see that the special counsel system failed because it relieved Congress of its responsibility to punish presidential misdeeds. The framers did not want legislators to hand off that duty to prosecutors or other branches of government. They understood that impeachment would place the ultimate constitutional responsibility in a body subject to political pressures and sensitive to other national concerns. Nevertheless, the Constitution makes Congress alone, not prosecutors, accountable for firing or keeping a president accused of abusing the office.

Mueller has recalled Congress to its constitutional duty; let us see if it is willing to answer.