Prime Minister kind of cross about being short? (7)

I believe the answer is:

trudeau

I'm a little stuck... Click here to teach me more about this clue!

'prime minister' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?

'kind of cross about being short?' is the wordplay.
'kind of cross' becomes 'tau' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'being short?' becomes 'rude' (I can't justify this - if you can you should believe this answer much more).
'tau' going around 'rude' is 'TRUDEAU'.

Can you help me to learn more?

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.