So when the referral for impeachment was sent to the House of Representatives, it was accompanied by a detailed record of what had transpired, comprising thousands and thousands of pages of documents and grand-jury transcripts. The facts were so little in doubt that the majority-Republican Judiciary Committee called only a single witness—Independent Counsel Starr—to summarize the case.

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When the matter moved to the Senate for trial, the House managers sought authority to call witnesses, but not because they needed more factual development. Rather, their argument was that the Senate, as a trier of fact, had to look the witnesses in the eye and assess their credibility. The senators did not need to ask, “What will Monica Lewinsky say?” because the record of what she would say was clear. Instead, the House argued, the Senate needed to ask, “Is Lewinsky telling the truth?” and to do that, it needed to hear from her directly.

But the Senate managed to dodge the question of credibility. After hearing opening statements from the House managers (who are essentially prosecutors) and from Clinton’s defenders, it rejected the House request to call 10 witnesses. After some negotiations, the Senate authorized the deposition of three witnesses, who were interviewed off the Senate floor with only a few senators present. Although the Senate allowed the House to call these witnesses, it appears to have decided the matter without assessing the witnesses’ credibility directly. The dominant view in the Senate seems to have been that even if everything Starr and the House alleged was true and even if the witnesses were fully credible, the offenses alleged (lying under oath about a private sexual matter) did not rise to the level of “high crimes and misdemeanors” worthy of impeachment. Whether witnesses were being truthful was almost beside the point.

If, last year, the House had chosen to act on impeachment in response to the report from Special Counsel Robert Mueller, one might reasonably think that the two impeachments were procedurally related. Both would have been grounded on an extensive pre-impeachment criminal investigation. But the House grounded its impeachment not in Mueller’s report but in the Ukrainian bribery scheme, and reached its decision to impeach Trump through a radically different process than was used for Clinton.

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There was no pre-impeachment criminal investigation of Trump’s efforts to compel Ukraine to pursue the alleged corruption of his political opponent. There were no lawyers and FBI investigators interviewing witnesses. There was no grand jury—merely the cumbersome House-committee process. That process didn’t last nine months; it lasted less than three. Rather than produce tens of thousands of documents, the White House and the executive branch withheld almost all those subpoenaed by the House. Likewise, rather than eventually allowing executive-branch witnesses to testify, the White House stonewalled the House inquiry: President Trump successfully frustrated the House’s efforts to hear from witnesses like former White House Counsel Don McGahn and former National Security Adviser John Bolton. And of course, President Trump never told his side of the story under oath.