What kind of trial gives you a verdict without witnesses or evidence? It’s called a cover-up.

If Senate Republicans stick together, that’s what will happen with the impeachment trial of Donald Trump.

On which side will Sen. Susan Collins land — cover-up or trial?

So far, it’s unclear. Maine’s senior senator has made comments that suggest she could be in favor of calling witnesses, but she has not demanded that they be called, as she did in 1999, when Democrat Bill Clinton had been impeached by the House. Back then, she said, “I need witnesses and further evidence to guide me to the right destination, to get to the truth.”

Her current position is troubling, because unless some Republicans break ranks, this will be a cover-up, not a trial.

Despite President Trump’s efforts to obstruct their inquiry, the House investigators have put together a strong case that shows that Trump used the power of his office to cheat in the upcoming election. Both directly and through intermediaries, Trump withheld support for the government of Ukraine unless its newly elected president announced an anti-corruption investigation into the family of Joe Biden, Trump’s potential opponent in the 2020 election. The House majority says that’s abuse of power, which is the first article of impeachment.

The administration’s attempt to smother the investigation is the basis for the second article of impeachment: obstruction of Congress. The president has forbidden government employees to speak with investigators and has ordered executive department agencies to withhold all documents relevant to the charges against him. But instead of viewing the missing evidence as proof that he is hiding something, Republicans are claiming that the lack of evidence makes the charge “weak.”

A complicit Senate could maintain those gaps in the record, letting the president off the hook and setting a path for future presidents who want to operate outside the law.

But the public will know. In the weeks since the House concluded its investigation, a number of facts have been exposed that were not available to House investigators.

On Jan. 2, the website Just Security published leaked, unredacted emails that revealed internal discussion among federal officials who were dumfounded about the status of $390 million in congressionally approved military aid for Ukraine. “Clear direction from POTUS to continue to hold,” wrote Michael Duffey, associate director of national security programs at the Office of Management and Budget.

On Jan. 6, former national security adviser John Bolton, who had refused to testify during the House impeachment hearings, announced that he would testify before the Senate if he were issued a subpoena. Bolton could offer first-hand testimony about what the president did to withhold support of Ukraine and why he did it.

Last week, the House was given a tranche of documents seized from Lev Parnas, a Florida businessman and confidant of Trump’s personal attorney, Rudy Giuliani. In interviews with the media, Parnas, who is under indictment for campaign finance violations, said he was authorized by Giuliani and Trump to threaten Ukrainian officials that they would lose all support from the United States unless they publicly announced an investigation of the the Bidens, and the documents appear to back him up.

And on Thursday, the nonpartisan Government Accountability Office delivered an opinion that the Trump administration’s handling of the aid to Ukraine violated the law.

All of these developments support the already-strong picture assembled by the House investigators of a president using the power of his office to cheat in an election and then covering up when he was caught. At the very least, senators should demand to see all the evidence and listen to every witness before voting on whether Trump should continue in office.

But last week, Collins appeared to dismiss the idea of opening the record to new information, telling CNN that the new revelations showed that the House had done an “incomplete job.”

That sounds like an argument for a trial that closes the books on new evidence, no matter how relevant it is to the matter at hand. That sounds like the justification of a cover-up.