Forgive me, I'm still reeling from the use of the word 'inspiring' in relation to the house of commons. Aside from inspiring me to riot I see little inspiration there but I'll admit perhaps that's just me.
Right, as to your query I think the answer lies within the behaviour common to ISTJs and ESTJs.
More obviously there are the styles of dress, the american power suit is something I'd think was more of an appeal to others that they are a mover and a shaker... sort of a "giz a job, I'm ded gud" as opposed to the more english style where everyone is wearing some kind of traditional suit but then where they get personal choice (ie the shirt and tie) you see some of the most god awful combinations.. that'd I'd read as more ISTJ (though I may be biased by my fashion unconscious ISTJ buddy).
America seems to have more hero worship in politics from my experience of them with the pres being almost deified (even if he's a certifiable idiot... *ahem*) where as our PM is most often shot to pieces by the opposition and his/her own party.
I believe there are also more remarks about how competitive the nation is as a whole being bandied about in the US as opposed to the UK.
Of course all of these little notes are quite subjective.. but there again is it not the same situation when typing an individual?
Basically if you look at what people expect from an American and an Englishman the expectations seem to match up closest to the ESTJ and ISTJ types respectively.
One thing that this is making me wonder is whether ESTJs object to their type this much..