Star Wars: 10 Massive Plot Holes The Prequels Stupidly Created
7. Why Was Leia A Princess?
When The Phantom Menace was released, everyone knew Padmé was Leia's mother. Not only did they share the same love of extravagant hairstyles, but the woman who would become Mrs. Vader was a Queen. How else would Leia be a princess?
Well, there's never an answer. Lucas quickly forgot why he made Padmé Queen in the first place, turning the role more of a ministerial one and the character into senator. It did help get the audience involved in the gradual crumbling of the Republic, but then left it open how Leia would be a princess; the title Queen wasn't carried over after Padmé left office.
No definite answer is given, but the implication is that because her adoptive father is senator of Alderaan she gets the honorary title. But that comes across as more than a little contrived. It would have been better if Lucas hadn't mentioned it at all; in referencing royalty everyone expected an airtight explanation of Leia's title.