The day after the 2016 election, I chatted with Dave Durenberger, the former U.S. senator from Minnesota with whom I was working on a book at the time. He'd been a never-Trump Republican in the just-finished election, going so far as to plant a Hillary Clinton sign in his yard.

"Now our institutions will be put to the test," Durenberger said that day. "We'll see if they are strong enough to stand up to what's coming."

His words echoed with me in the past two weeks as U.S. House Democrats and Speaker Nancy Pelosi launched a formal impeachment inquiry into the constitutionally questionable conduct of Republican President Donald Trump.

Since Pelosi's Sept. 24 announcement, the nation's pundits have been working overtime to forecast the political implications of her caucus' move. I'll leave them to it.

My thinking has run more along the line to which Durenberger pointed nearly three years ago. There's more at stake in the new impeachment probe than its consequences for the 2020 election. There's also the question of whether the checks and balances that are a hallmark of America's representative democracy can survive the Trump presidency's assault on the nation's governing traditions, norms and rules of law.

As speaker, Pelosi is more than her party's leader. She is also the chief steward and protector of a crucial institution in America's separated-powers scheme of government. And that institution's vitality — long on the wane relative to the executive and judicial branches — looks to be at risk of major erosion if House Democrats do not at least brandish the constitutional hammer of impeachment now.

Give Trump a pass on holding up congressionally authorized aid to a foreign government in order to coerce that government to dig up dirt on his political rivals, and little would be left of the claim that Congress serves as a check on presidential misconduct. Trump's self-serving solo act would become the new normal in the exercise of American power.

Refuse to begin impeachment proceedings, which afford the House more legal authority to compel testimony, and congressional oversight is likely to be reduced to farces like the Sept. 17 appearance of former Trump aide Corey Lewandowski before the House Judiciary Committee. Trump's team will just keep scorning, stonewalling and skipping town when Congress calls.

And after Trump? A day could come when Americans wonder why they bother to elect a Congress at all. And if it does, a lot more Americans will also chafe, and rebel, at the sense that their government has slipped out of their control.

Lest I carry my worry about the weakened condition of Congress too far, I checked in with a coolheaded congressional insider who can take the long view. Democratic Fourth District U.S. Rep. Betty McCollum is now serving her 19th year, making her the second-most senior member of the Minnesota delegation.

McCollum has seen a lot. I thought she might cool my jets. Instead, McCollum sounded every bit as concerned that Trump's presidency is putting America's separation of powers at risk.

"This president flagrantly ignores the checks and balances provided in the Constitution," she said, reciting examples ranging from the refusal to release his tax returns to ignoring congressional subpoenas to holding up $391 million in aid to Ukraine, intended by Congress to help that nation resist Russian aggression.

"This callousness to the rule of law goes all the way down this administration to the deputy agency heads. Thank goodness people are now finally brave enough to stand up and fight back," she said, mentioning Minnesota freshman Democratic Reps. Angie Craig of the Second District and Dean Phillips of the Third. Both announced support for an impeachment inquiry shortly before Pelosi acted. "They are saying, 'This isn't about my re-election. This is about my country.'"

McCollum is quite aware that, to date, few Republicans in Congress or in the country see the impeachment inquiry in the same institutional light. She's under no illusion that the Senate's Republican majority will convict Trump if the House impeaches him. But making an effort to check an overreach of presidential power will still be worthwhile for the House, she maintained. It will flex an institutional muscle that is at risk of atrophy if it goes unused now.

"Our oath is to defend and protect the Constitution of the United States, not to defend and protect the president," she said. "We don't glorify and worship the president in this country. He's just a man, and in my opinion, a flawed one. I have faith in the Constitution and the American people. I think at the end of this, our country will remain divided, but many of us will find unity of purpose in the honoring of our Constitution."

House Democrats will do well to keep the U.S. Constitution, and not partisan point-scoring, at the fore in coming weeks. If they do, their institution will be the stronger for it, no matter the impeachment inquiry's outcome.

Lori Sturdevant is a retired Star Tribune editorial writer. She is at lsturdevant@startribune.com.