Robert Mueller’s recent statement just emphasizes what was already clear from the redacted report of his investigation: the president repeatedly tried to terminate, obstruct or guide the special prosecutor’s investigation, including trying to oust Mueller himself. That is to say there is reason to investigate whether he committed crimes.

Mueller also made clear that under Justice Department policy, a sitting president may not be indicted. The remedy, he says, lies outside the criminal justice system. He means impeachment. The Constitution stipulates that any federal official may be removed from office if found to have committed “high crimes or misdemeanors.” The exact meaning of that phrase has never been defined, but obstruction of justice is a clearly defined crime.

The House of Representatives is charged with deciding whether to impeach; the Senate must then try the case and decide whether to convict. The House may impeach by majority vote, but the Senate may only convict by two-thirds vote.

With the Senate under Republican control and most Republican Senators remarkably loyal to President Trump, reaching that two-thirds threshold to convict is essentially out of the question. Public opinion at this point is narrowly against impeachment. Only Democrats favor it. Republicans overwhelmingly oppose it. This political environment puts little pressure on Republican senators to defect.

Thus the Democrats who control the House of Representatives have good reason to investigate the president and to consider impeachment, but the president and his administration are adamantly refusing to cooperate. The House can probably prevail in court — eventually — but Trump may be able to run out the clock. But why even bother if a Senate conviction is not in the cards?

Political prudence thus may counsel House Democrats to stay away from impeachment because it is bound to fail in the Senate and would serve only to outrage and mobilize Trump’s supporters. Trump himself apparently sees it this way and welcomes an impeachment.

But both legal strategy and high principle push the other way. If the House were to officially start an impeachment inquiry, pursuant to an eventual vote on whether to impeach, then the courts would most likely rule that the president and the administration may not obstruct Congress in carrying out its constitutional duty.

There is no higher constitutional duty than to assure that a president who has committed crimes be brought to account. The House will finally have to vote to impeach, or be accessory to Trump’s violations. It should move deliberately but it will have to act in the end. Maybe by that time enough independent voters will come to see the need for impeachment to change the calculus for Senate Republicans. It is unfortunate that most Republican voters will stick with the president no matter what he is shown to have done. Thus impeachment will be inevitably partisan.

But remember that in both the Nixon case and the Clinton case, most voters, members of Congress and Senators of the president’s party stuck with him. In the former, enough Republican Senators defected to make conviction likely. That’s when Nixon resigned. With Clinton, there were not enough Democratic defections to convict him. In both cases it was the opposition party that carried the burden of impeachment and conviction. That is what we have an opposition for.

Trump will probably be impeached but not convicted. Wounded, he will then fail to get re-elected.

But by voting for impeachment the House will have struck a blow for the integrity of the Constitution and the rule of law. Future presidents will imitate Trump at their peril.

John Peeler is a retired professor of political science at Bucknell, where he taught Latin American politics. He lives in Lewisburg.