LOL. I am pretty sure that you don’t mean mock as a verb (‘to tease or laugh at in a scornful or contemptuous manner’), v. an adjective (‘not authentic or real, but without the intention to deceive’), but with students, who knows! “Model Senate” like “Model UN” is a well-understood construct.
In general, Cambridge is less welcoming to US applicants, but PPE at Oxford gets the highest number of US applicants so there is a lot of competition from other people with US qualifications. FWIW, in the 2016/2017 application cycle 605 of the 1983 PPE applicants were non-EU internationals; they received 175 of the 705 interview invitations; and 53 of the 274 offered places. Note that in that cycle a total of 450 non-UK/non-EU students were admitted (across all courses - about 14% of the overall offers), of whom 180 were US domiciled.
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