NEW YORK (AP) — President Joe Biden spent only a weekend as the "Hamburglar" in the conservative media world.

But while the false story lasted, it moved with a damaging speed and breadth, another example of a closed ecosystem of information affecting public opinion.

An academic study published a year before Biden became president was used to speculate that he would place limits on how much red meat Americans can consume as part of his stated goal to sharply reduce greenhouse gas pollution.

It was a potentially potent, visceral argument with punchy cable TV octane, namely that Biden was trying...