The U.S. House's historic vote to impeach President Donald Trump comes near the end of the president's third tumultuous year in office — which is also the third year of the prolonged stress test he's been giving to the U.S. Constitution. It's an occasion to check in on the most basic question that can be asked in a democracy: What is the state of our Constitution?
The short answer is that the Constitution is, so far, holding up in the face of the most extended challenge to its principles and norms that it has confronted since World War II. The impeachment itself is actually a significant improvement in the Constitution's performance. It signals that at least half the legislative branch — the House — is now taking seriously its own responsibility to uphold the Constitution in the face of presidential contempt for it.
Until now, it's the other branch of government — the judiciary — that has been almost the only effective check on Trump's recurring impulse to violate the Constitution. When Trump has signed executive orders that break the Constitution, courts have often struck them down. The courts have also blocked other unlawful executive branch action. So when it comes to the formal constitutional rules that courts interpret and apply, the Constitution has been functioning remarkably well since January 2017.
Where the Constitution has been faltering is in the significant erosion of our informal, unwritten norms. These have constitutional weight even if they aren't identifiable as strict rules of constitutional law. They include things like the politicization of the Department of Justice and the FBI and the subtle corruption of the presidency through Trump's continuing pursuit of his business interests while in office. For most of the last three years, Trump has successfully undercut those kinds of hard-won, unwritten norms.
Since taking office, Trump has committed a wide range of acts that could plausibly be classified as impeachable high crimes and misdemeanors. The House chose not to impeach him for those — like the obstruction of justice described in Robert Mueller's report — but for high crimes and misdemeanors that specifically violated the constitutional principles of democracy and the separation of powers.
The first article of impeachment, for abuse of power, stands for the House's insistence that the Constitution prohibits the president from using his office for personal political gain, and from corruptly influencing his own re-election with the help of a foreign power. Although no statute clearly prohibits this conduct, it's barred by the Constitution itself through the clause that prescribes impeachment for "high crimes." The impeachment puts flesh on the bones of basic principle that the president can't try to break democracy.
The second article, for obstruction of Congress, stands for the principle that the president can't stonewall the legislative branch and thus render himself beyond the reach of the Constitution. Here the House is vindicating the principle of separation of powers. Here, too, there is no legal provision saying the president can't refuse to cooperate in an impeachment inquiry. But it's a principle embedded in the Constitution itself — specifically in the logic of Congress's authority to oversee the president.
Impeachment on its own is only part of what the legislative branch should do to stand up for the Constitution. If, as seems likely, the Senate does not remove Trump, it could imply that Trump's conduct is acceptable. The result could erode constitutional norms still further.
