Late on the night of Jan. 30, as the Senate debated whether to call for witnesses and other evidence in the impeachment trial of President Trump, Sen. Angus King paused in his note-taking just long enough to scrawl a rhetorical question on his legal pad.

“How can anyone vote no?” he asked himself.

So much for logical analysis.

U.S. Sen. Angus King

“I honestly thought that midway through that process, the Republicans were going to caucus and they were going to revolt and they were going to tell (Senate Majority Leader) Mitch (McConnell), ‘We’ve got to do this. This makes us look awful,’” King recalled in a telephone interview Friday morning. “And it never happened.”

Thus, the record now shows that for the first time in the nation’s history – spanning the impeachments of two past presidents and 14 federal judges – this most solemn proceeding concluded without one witness or one piece of subpoenaed evidence. Not one.

“I was overly optimistic on that one,” King conceded as he waited to board his flight to Portland. “I don’t know how you go home and say, ‘Well you know, I didn’t really want the facts.’”

While all eyes have fixated on Sen. Susan Collins and whether she’d support the calling of witnesses (she did) and ultimately vote to convict Trump (she didn’t), King has attracted attention of his own with his argument that this is about far more than a president whose interest in the future of this country begins and ends with himself.

By giving Trump a pass on his blatant attempt to strong-arm Ukraine into aiding his re-election, King maintains, the Senate’s Republican majority did permanent damage, now and forever, to Congress’ status as a co-equal branch of government.

“I don’t know what Donald Trump will do or not do in the next year or four years or five years, but I’m talking about 10 or 20 years from now,” King said. “This is a powerful precedent. We were still talking this week about stuff that happened in the Andrew Johnson trial of 153 years ago. That’s the deeper issue that bothers me – what does this mean for the fundamental balance of power?”

It’s a balance that, in King’s view, has been eroding steadily for the past 70 years, from who under our system of government can declare war, to who oversees trade policy, to who controls the power of the purse. That said, as King wrote last week in an op-ed for Time magazine, “this is the latest – and greatest – transfer of power from the Congress to the President in American history.”

Meaning?

Well, if you’re a Trump fan, it means be careful what you cheer for. With the legislative branch so diminished, this presidential cover-up inevitably will breed more presidential cover-ups. Just as the Congress that cowers today sets the stage for the Congress that quakes tomorrow.

And if you’re not a Trump fan? How can you watch what just happened – not to mention what didn’t happen – and feel optimistic about the future?

The short answer is you can’t. Emboldened by his own acquittal, his highest-ever approval rating of 49 percent and Democratic meltdown in Tuesday’s Iowa presidential caucuses, Trump emerges from last week riding a wave that could well carry him to re-election in November.

Some have said all along that the voting booth, not impeachment, offers the best antidote to Trump’s laundry list of corrupt behavior over the past three years. King himself told the Senate last week that he was a “conservative” on impeachment – that is, before Trump got caught corrupting the looming presidential election.

“In normal circumstances, the argument of the president’s defenders that impeachment is not necessary because the election is less than a year away would be persuasive,” King told his colleagues on Tuesday. “But the president was attempting to undermine that very election – and he gives every indication he will continue to do so.”

Which means, for all the talk of Wednesday’s impeachment vote bringing an end to this sordid chapter in U.S. history, it is more likely just the beginning. Contrary to Collins’ ridiculous assertion to CBS on Tuesday that Trump has learned a “pretty big lesson” from his impeachment – she later backpedaled to say her comment was “aspirational” – the painfully obvious truth is that Trump has learned nothing. He will, no doubt, offend again.

Even King, ever the optimist, finds himself struggling with that realization.

“There’s a larger issue here of does the truth matter?” he said. “Are we in an age where there’s no such thing as a fact and there are ready justifications for just about anything?”

Time will tell. But if you’re looking for some way out of this morass, King suggests you take a peek back at the 2016 election. Not the 129 million or so people who voted for either Trump or Hillary Clinton, but the 121 million people of voting age who never cast a ballot at all.

His point: Even as Congress abdicates its responsibility to hold the executive branch accountable, one line of defense remains. To those who now say there’s no hope, that a trial without witnesses is a miscarriage of justice, that the system, as Trump himself likes to say, is indeed rigged, the senator whose worries extend far beyond Donald J. Trump has a simple answer.

“I think my response will be, as it’s been all my life, if you don’t like it, vote,” King said. “That is the ultimate check in our system.”