It's mostly a gagfest, but I Zoidberg is well motivated and there's some entertaining political commentary as well.

Well, I have to disagree with my earlier comment about a year ago. On rewatch, I love the political commentary in the episode as much as I love the brilliant humor of it, but more than anything, I appreciate how it's a character-focused story of Zoidberg. It tells a tidy-little tale about Zoidberg's shifting impulses, from his love of Earth, to his sense of betrayal at his being punished for exercising his freedom, to the rekindling of his love when he sees the people from his old planet stomping freedom out and the Earthikans fighting for it. There's a sweet, almost immigrant pride story there, that adds some heft to the enjoyable silliness of Nixon's usual amusing fascism, the jabs at the Supreme Court, and the entertaining if fairly thin commentary on the flag-burning controversy in the United States.