Bangladesh, May 21 -- For years, Americas corporate media insisted it was a fearless watchdog, ever-vigilant in its scrutiny of power. But the last four years have shown just how selective that scrutiny can be. While the press hounded President Donald Trump with endless speculation about his mental and physical health-often based on little more than armchair diagnoses and anonymous sources-it offered Joe Biden a protective media cocoon, allowing a shadow presidency to unfold in plain sight.

Now, with Biden no longer seeking re-election and the consequences of his incapacitation impossible to ignore, legacy outlets have suddenly rediscovered the concept of presidential fitness. But this newfound interest isnt a sign of journalistic integr...