That headline, while meant to be amusing, is contemplating a rather broad definition of the historical political metaphor. The term “lame duck” actually predates its use in politics (according to Wikipedia), and was first used in a political sense in America in 1863. Political cartoons depicting lame ducks date back over a century. Used in the traditional sense, the term refers to the period between when politicians lose their bid for re-election and when the new Congress and/or president is sworn into office. The congressional session after the November elections but before the new Congress is sworn in has long been known as the “lame-duck Congress.”
But the term can also be used to describe a politician who is barred from even running for re-election by term limits. In this case, the timing of when the lame-duck period begins is a lot looser. Some second-term presidents are labelled lame ducks at the very start of their second term, for instance, others get the label applied after the midterm congressional elections take place, and some skate all the way to the final few months of their administration (the traditional congressional lame-duck period) before having the term used about them.