Donald Trump's alleged efforts to destroy or hide some records of his presidency initially looked cartoonish, including documents found stuffed in a toilet and boxes of records recovered from his Florida resort. The recent discovery of more than seven hours of missing phone call records from Jan. 6, 2021, the day when his supporters breached the Capitol, raises concerns about a potential cover-up. But there is a more fundamental issue. Regardless of whether the gap in Trump's phone records arose from happenstance or skullduggery, it illuminates a broader and disturbing pattern: The modern presidency can facilitate cover-ups, and a president's enormous power to control information and keep secrets can impede the effective working of democracy. As historians of the modern presidency, we've spent decades examining memoranda of conversations, phone recordings and records, classified documents, and much more. All presidents want to shield aspects of their decision-making from public scrutiny. Much of the work of historians involves unearthing and deciphering what presidents did not want known while they were in office. The tension between policymakers and historians is natural. Unexplained gaps in historical record are not. In our experience, they almost always signal broader misdeeds.