The discrimination isn't a whole country thing rather it's state
level thing.
Look at the Texas constitution:
Sec. 4. RELIGIOUS TESTS. No religious test shall
ever be required as a qualification to any office, or public trust,
in this State; nor shall any one be excluded from holding office on
account of his religious sentiments, provided he
acknowledge the existence of a Supreme Being.
http://www.constitution.legis.state.tx.us/index.aspx
This is something like a tactic to gain votes..........majority
of the population are christains then