During Donald Trump's second impeachment trial last February, his lawyers argued that he bore no responsibility for the riot that interrupted the congressional tally of Joe Biden's electoral votes on Jan. 6 because "the breach at the Capitol was planned several days in advance." In their view, that meant the violence had nothing to do with the inflammatory speech that Trump gave that day, during which he urged his supporters to "fight like hell" and "stop the steal." That defense elided the months that Trump spent promoting the fantasy that systematic election fraud had deprived him of his rightful victory,...