As a foreigner, I find it astonishing that religion plays such a large part

[Silent3]

7. You've had to be some kind of Christian in the US for a long time, however

...to have much of a hope of winning high elected office. While the culture wars have heated up in the past 30 years since Reagan, there hasn't ever been a time where non-Christians would fare well here, with perhaps the exception of the occasional Jew here and there, and some of the deists of the American Revolution.

Don't forget that it was in the 1950's that "under God" was crammed into the Pledge of Allegiance. "In God We Trust" as been on coins since 1864, it became the official motto of the US in 1956, and was slapped on paper currency in 1957.