When President Kennedy visited Berlin, he said…
“Ich bin ein Berliner” (“I am a Berliner”).
Now what if he had visited Hamburg instead?
“Ich bin ein Hamburger”?
Frankfurt?
Or Vienna?
Bangkok may have been appropriate, all things considered. 
If it had been Denmark that had somehow had a wall built around it, would Kennedy have said, “I am a Danish”?
Close. A “berliner” is a jelly donut.
Nuremburg?
“Ich bin ein slider”?
He probably would have got kicked in the head by a gang of young toughs jealous over the attention their women were paying him.
What if he had likened himself to someone born in a certain little village in Austria (known for having its signs repeatedly stolen by visiting English speakers), but who has lived in Berlin for most of his life?
(ETA: I just now realized I came this close to unintentionally Godwinizing this thread…)
You’re OK there, I think – haven’t heard that Braunau-am-Inn gets its town-limits signs stolen much, by visiting speakers of any particular language 
…
Was going to carry on with the “almost-Godwinizing” humour; but took several glitches in a row stopping me from successfully “submitting reply”, as a sign suggesting that laying-off was indicated.
Yes, I think the joke was that he would then have said “ich bin ein Fucking-Berliner.”
Yup. Sorry if I was too vague – but I’m glad that Siam Sam and I think alike!