When it was over, the impeachment of U.S. President Donald Trump produced 135 days of partisan rancour, 17 witness accounts, more than 28,000 pages of documents and testimony, and one big loose end. The impeachment inquiry provided a remarkable inside view of a White House effort to secure politically beneficial investigations by Ukraine’s government at a time when Trump is seeking re-election. But – whether one ascribes the shortcoming to Democrats’ haste in their investigation or Trump’s recalcitrance – it yielded little direct evidence of what happened inside the Oval Office itself. The Democratic-controlled U.S. House of Representatives voted to impeach Trump in December without hearing from the aides who dealt with him directly, after Trump directed officials not to cooperate with the inquiry. The U.S. Senate acquitted him on Wednesday without hearing from them either. In public and closed-door testimony, White House aides detailed an effort to withhold nearly $400 million in security aid and a coveted White House visit unless Ukrainian officials announced the investigations Trump sought into his Democratic political rival, Joe Biden, and his son, Hunter Biden. That exchange was at the center of the House charge that Trump abused his power for political benefit. But because almost none of the aides who testified had spoken to the president about the issue, their accounts left one central question largely unanswered: What did Trump himself do? Trump’s former national security adviser, John Bolton, appeared last week to be on the cusp of supplying an answer when The New York Times reported he had written a book claiming that Trump told him he would not restore security aid to Ukraine until it launched the investigations he wanted. Bolton said he would testify if the Senate subpoenaed him. In his as-yet-unpublished manuscript, Bolton said Trump discussed the aid freeze with him in August, more than a month after it began. That account appeared to leave unanswered how and why Trump ordered the aid frozen in the first place, why it was ultimately restored and how closely Trump associated benefits to Ukraine with political favours. “We have demonstrated, we believe, that the scheme was entirely corrupt,” said Representative Adam Schiff, the head of the group of House Democrats who prosecuted Trump. But he told senators: “If you have any question about that, ask John Bolton.” In the end, Trump’s fellow Republicans in the Republican-controlled Senate suggested the answer did not really matter. Whatever Trump’s involvement, several senators said, the pressure campaign was not the type of wrongdoing for which they were willing to remove a president from office for the first time in U.S. history. “While we can debate the president’s judgment when it comes to his dealings with Ukraine, or even conclude that his actions were inappropriate, the House’s vague and overreaching impeachment charges do not meet the high bar set by the founders for removal from office,” said Senator John Thune. Senators also acquitted Trump of a related charge of obstructing the House impeachment investigation.