The contrast between these two statements reveals everything about the challenge of exercising Article II, Section 4 of the Constitution and attempting to remove President Trump from office. By now, the “unfit” condition of this magistrate is clear, as is his disdain for the principles and traditions of American public life. But the fitness of Congress, the sole branch empowered to impeach and convict the president, also bears scrutiny.

Is the least-trusted institution in America — rated lower than big banks, the news media and the presidency itself — ready to investigate and try a president in a way that conveys legitimacy and inspires broad confidence? And could the American public, already so divided and cynical, regard whatever outcome emerges from that process as nonpartisan and fair?

These questions loom over the numerous guides and retrospectives on presidential impeachment — authored by historians, law professors, journalists and assorted commentators — that have appeared in the two years since Trump swore the oath of office. (For some reason, many publishers imagined that a refresher might come in handy.) Partisanship, they contend, poisons impeachment, both the process and its legacy. This is the paradox: When a demagogic or authoritarian leader comes to power by stoking cultural division and partisan hatreds, the need for impeachment grows, but so does the difficulty of seeing it through.