President Donald Trump shakes hands with James Comey, then–director of the FBI, during an Inaugural Law Enforcement Officers and First Responders Reception in the Blue Room of the White House on January 22, 2017, in Washington, D.C. Andrew Harrer-Pool/Getty Images

When Donald Trump abruptly fired FBI Director James Comey on Tuesday evening, it sent off shock waves of concern that the president was seeking to protect himself and his associates from the FBI’s investigation into possible connections between Trump’s campaign and the Russian government. The news — and President Trump’s Wednesday morning Oval Office appearance beside Henry Kissinger — triggered abundant references to President Nixon’s Saturday Night Massacre and questions of whether Comey’s dismissal has precipitated a constitutional crisis. Democratic legislators like John Conyers and Keith Ellison, as well as ACLU national legal director and Georgetown Law professor David Cole, have all answered that we are indeed now in a constitutional crisis. But most legal experts weighing in disagree.

Part of the challenge in answering the question is that there are several ways of defining a constitutional crisis, says David Pozen, a professor of constitutional law at Columbia University, who served as a clerk for both Supreme Court Justice John Paul Stevens and Judge Merrick Garland, and as special assistant to Ted Kennedy on the Senate Judiciary Committee.

One definition, Pozen told the Voice, is “officials refusing to comply with the Constitution. That isn’t really implicated here — legally speaking, the president has the right to fire the FBI official. The breach is one of norms than of formal law.”

Alternately, Pozen says, a constitutional crisis might be understood to be a situation in which the Constitution itself prevents the political system from dealing with major threats — but that’s not really accurate in this situation.

A third definition would be a situation in which there’s a loss of faith in the Constitution by the public or large segments of the public, Pozen says, but this definition isn’t exactly applicable now either.

“Comey’s dismissal may well be a political and democratic crisis,” Pozen says, “but it’s not a constitutional one.”

“If there’s a constitutional concern here, it’s at one remove,” he says. As an independent actor, Comey might yet have uncovered constitutional issues: entanglement with a foreign power, emolument issues, other problems as yet unforeseen.

“This looks like a preemptive strike against someone who might have wielded oversight,” Pozen says, “and in that sense we should be worried, constitutionally, that we will be less likely to get the production of constitutional accountability from this important office in the future.”

Even so, political appointees in the executive branch aren’t where anyone should be looking for constitutional checks on the presidency, Pozen says. The real constitutional checks on presidential power remain where they’ve always been: in the judiciary and in Congress.

Senate Minority Leader and New York senator Chuck Schumer seems so far to be taking that responsibility seriously.

“The dismissal of Director Comey establishes a very troubling pattern,” Schumer told his peers on the Senate floor this morning. “This administration has now removed several law enforcement officials in a position to conduct independent investigations of the president and his administration — from Acting Attorney General Sally Yates to Preet Bharara, and now Jim Comey.”

The official explanation given by the White House, that Comey was fired for violating protocol in his public criticism of Hillary Clinton last year even as he exonerated her of unlawful activity, doesn’t hold water, Schumer said, given the timing of his dismissal, and it also raises serious questions:

Why was Attorney General Sessions, who had recused himself from the Russia investigations, able to influence the firing of the man conducting the Russia investigation? Did Deputy Attorney General Rosenstein act on his own or at the direction of his superiors or the White House? Are reports that the president has been searching for a rationale to fire the FBI director for weeks true? Was Director Comey’s investigation making significant progress in a direction that would cause political damage for the White House? Why didn’t the president wait for the inspector general’s investigation into Director Comey’s handling of the Clinton email investigation to conclude before making his decision to fire him? Was this really about something else?

The only acceptable solution, Schumer said, is for the Justice Department to appoint a special prosecutor to continue Comey’s investigation into the Trump camp’s connections to Russia.

Schumer’s remarks came before the New York Times and the Washington Post broke the news this morning that Comey was fired shortly after requesting more funds to pursue his investigation into the Russian connections.

But Schumer and his party are in the minority in the Senate and the House of Representatives, and so far most Republicans haven’t joined him in demanding a special prosecutor.

If the legislature isn’t prepared to check executive power, we might have a real problem. The courts have so far served as a powerful bulwark against the Trump administration’s efforts to unconstitutionally restrict immigrant rights, but they’re not well equipped to investigate the question of whether the president and his associates unconstitutionally colluded with the Russian government. If Trump installs a loyal stooge at the FBI and Congress remains compliant, there might be no reliable way to identify or prevent constitutional abuses in the executive. And that, at the very least, might trigger the third sort of constitutional crisis Pozen outlines: a crisis of public confidence in the Constitution.