Samuel G. Freedman, a professor of journalism at Columbia University, is the author of eight books, including "Jew vs. Jew: The Struggle for the Soul of American Jewry." The views expressed in this commentary are his own. View more opinion articles on CNN.

(CNN) For a man with too much to say about too many things, President Donald Trump has maintained atypical restraint in the 17 days since since the dissident journalist Jamal Khashoggi disappeared into the Saudi Arabian consulate in Istanbul and was presumably murdered inside it by agents of the regime.

Samuel G. Freedman

The president groundlessly asserted that "rogue killers" could have committed the crime. Then he retreated even farther to plead that the de facto Saudi dictator, crown prince Mohammed bin Salman, should not be undeservedly suspected in the apparent assassination of a prominent political opponent.

All the president's evasiveness has set off speculation about what conflicted interests might explain it -- Trump's longtime business dealings with wealthy Saudis, his brokering a major arms deal with Riyadh for American defense contractors, bin Salman's importance to American efforts to isolate and confront Iran.

Valid as those theories seem, they omit one other obvious reason for President Trump's striking indifference to the likely slaying of a journalist who was, after all, a resident of the United States for the past several years and a regular columnist for the Washington Post. Quite simply, if a government indeed killed a bothersome journalist, then that action is just the logical, if ghastly, extension of Trump's campaign to vilify and endanger journalists in the United States.

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During both his campaign and his White House reign, President Trump has referred to journalists as "disgusting," "crooked," "dangerous," and, most significantly, as "the enemy of the American people." That phrase, closely echoing Josef Stalin's, all but invites the Stalinist solution to such treason: perhaps the show trial, perhaps the Gulag cell, perhaps the executioner's bullet.