In this image from video, Chief Justice of the United States John Roberts presides Friday over the Senate as a Court of Impeachment against President Donald Trump.

It seems it was half a trial.

Those are not our words about the Senate's impeachment trial of President Donald Trump — which will stretch into next week even though Republican senators showed a collective refusal Friday to hear any witnesses who might pile on more evidence of the president's guilt of abuse of power and obstruction.

Actually those words — "It seems it was half a trial" — are from retired four-star Marine Gen. John F. Kelly, President Trump's former chief of staff and secretary of homeland security.

And Kelly, talking to reporters with NJ Advance Media, was only half done talking.

"If I was advising the United States Senate, I would say, 'If you don't respond to 75 percent of the American voters and have witnesses, it's a job only half done,'" he said. "You open yourself up forever as a Senate that shirks its responsibilities."

(MORE: Trump acquittal now likely Wednesday; Senate rejects witnesses)

It is a Senate that is shirking its responsibilities. And atop the list of shirkers is Tennessee Sen. Lamar Alexander — one of four swing-vote GOP senators who for weeks was said to be on the fence about the need for additional witnesses. But on Thursday night, Alexander proved once again that he's no Howard Baker — the former U.S. senator from Tennessee long said to be Alexander's mentor.

Rather than do the right thing and vote to allow witnesses to tell what they heard and saw President Trump do as he tried to extort free opposition research on a political opponent from a foreign government by withholding military aid that we paid for and Congress allocated, Alexander in a long statement acknowledged Trump's wrongdoing. Then he gave him a pass.

Baker, a stalwart Tennessee statesman, did exactly the opposite. Eventually seeing the malevolence of Richard Nixon, also a fellow Republican, Baker helped force that president's resignation before impeachment was consummated.

Not so, Alexander.

In fact, Alexander noted that House managers had "proved" Trump's guilt, and he called Trump's actions "inappropriate." But then he choked and said he felt "it does not meet the United States Constitution's high bar for an impeachable offense."

(MORE: Read Sen. Lamar Alexander's full statement)

There was no need to consider the "frivolous" second article of impeachment that would remove the president "for asserting his constitutional prerogative to protect confidential conversations with his close advisers," Alexander said.

In other words, it's OK to cheat, bribe and obfuscate. Just pull down the curtain of government and do it in secret. And with that, Alexander tossed the cleanup problem back to the American people — the voters.

On Friday, Republican Sen. Lisa Murkowski also came out against calling for additional witnesses and documents in President Trump's impeachment trial, all but assuring acquittal.

This majority Republican Senate doesn't want more witnesses and documents. They don't want more proof. They don't want truth.

They can't handle the truth.

Americans can. We can smell it. And it stinks.

It is up to voters, and there must be a reckoning.