Presidents are held to account according to a process defined by a Constitution that establishes a system of checks and balances. If there is a Congress that disregards the Constitution, as the United States suffered with during the desultory tenure of House Speaker Paul Ryan, accountability is off the table. If the United States has a Congress that takes its duties to the Constitution and the American people seriously, as it now does with the Democratic majority that voters empowered in November, the checking and balancing will proceed at a pace appropriate to the threat posed by a commander in chief who can no longer be allowed to govern with impunity.

This is not the only way in which a president can be sanctioned, as the remarkable testimony of Michael Cohen to the House Oversight and Reform Committee reminded Americans just last week. A president and his associates can be the subject of an inquiry by a special counsel, such as Robert Mueller, or by the able federal investigators and prosecutors of the Southern District of New York. If half of the inquiries that Cohen discussed come to fruition, there is every reason to believe the Donald Trump will face many days of reckoning.

But the accountability process that is managed by Congress remains the essential one when we are discussing the actions of a sitting president. Once this process has been initiated, the prospect of accountability becomes dramatically more real. Indeed, if this remains a constitutional republic governed by rules and not men, then the congressional processes hold out the possibility that a necessary level of accountability will be achieved during the course of a presidency—not after it is finished.

That necessary level of accountability can take many forms, including the impeachment of a sitting president by the House and conviction by the Senate, resignation in disgrace by a president who fears the process, or defeat at the polls for a president and those members of Congress who thwart a legitimate process. Related Article Michael Cohen Destroyed Not Just Trump but Also His House GOP Defenders Joan Walsh

It is in this context, and with this understanding, that Americans should consider—and welcome—the announcement by House Judiciary Committee chair Jerry Nadler that “we will be issuing document requests to over 60 different people and individuals from the White House to the Department of Justice, Donald Trump, Jr., Allen Weisselberg, to begin the investigations to present the case to the American people about obstruction of justice, corruption and abuse of power.”

Nadler, the chair of the key committee when it comes to the processes by which Congress might achieve formal and full accountability, respects the process. He recognizes that impeachment is a political act—as opposed to a legal one—and that as such it is important to bring the people and House members from both parties along. He is not getting ahead of himself, or of the Congress.

But on Sunday he explained, in conversation with George Stephanopoulos on ABC’s This Week, that Trump fixer Michael Cohen’s public testimony before the House Oversight and Reform Committee had expanded the sense of this moment’s urgency and consequence.

“[What] we learned from the Cohen testimony,” said Nadler, “is that he directly implicated the president in—in various crimes, both while seeking the office of president and while in the White House.”

Nadler strikes an appropriate balance as the chair of the Judiciary Committee. “Impeachment is a long way down the road,” he says. “We don’t have the facts yet, but we’re going to initiate proper investigations.”

While impeachment may still be “down the road,” these appropriate investigations will involve potentially impeachable offenses.

For instance, Cohen’s testimony last week drew attention to alleged violations of campaign-finance laws and other actions by the president that might reasonably be understood as assaults on democracy during and after the 2016 presidential election.

Nadler says that “seeking [to] sabotage a fair election would be an impeachable offense.”

The Judiciary Committee chair also says, “It’s very clear that the president obstructed justice.” How? “Eleven hundred times he referred to the Mueller investigation as a witch hunt.… he tried to protect (retired Lieutenant General Michael) Flynn from being investigated by the FBI. He fired Comey in order to stop the Russian thing, as he told NBC News.… He’s intimidated witnesses—in public.”

That’s a damning list of accusations. It reads like an article, actually many articles, of impeachment. To get to the point where those articles are written and approved by a Judiciary Committee majority (of Democrats and, ideally, constitutional-conservative Republicans), however, inquiries and investigations must proceed, hearings must be held, witnesses will almost certainly have to be subpoenaed.

It really is a process. And this particular process will, undoubtedly, intersect with and extend from the inquiry into Russian interference in the 2016 election that is being conducted by special counsel Robert Mueller. It will also intersect with and extend from other inquiries, by federal prosecutors with the Southern District of New York. And with the investigations and hearings conducted by other congressional committees, including the House Oversight Committee and the House Ways and Means Committee—where committee chair Richard Neal (D-MA) has reportedly directed lawyers for the committee to prepare a request for the president’s tax returns.

The Constitution establishes an infrastructure of accountability for presidents. That infrastructure sat dormant for the first years of Donald Trump’s presidency. Now, the switch has been flipped. The machinery has been turned on.

“The Republicans spent two years shielding the president from any proper accountability,” says Jerry Nadler. “It’s our job to protect the rule of law. That’s our core function. And to do that we are going to initiate investigations…into corruption and into obstruction of justice.”