Movies
Oh, but you can't expect to wield supreme executive power just because some watery tart threw a sword at you!
— Dennis • Monty Python and the Holy Grail

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Legitimacy gets mocked here through a deliberately silly image. Reducing a claim to power down to an arbitrary gesture involving a sword and a stranger pokes fun at how flimsy the basis of authority can sound once stated plainly. The humor undercuts any grand justification.
Context reviewed