Belief in political office, required?

As of September 14, Julia Gillard is the Prime Minister of Australia.  During the election candidate Tony Abbott of the Liberal Party (which is actually conservative in American terminology) was careful to proclaim his strong Christian beliefs, as would seem to be required.  Gillard, however, took another tack during a radio interview:

FAINE: Do you believe in God?
PM: No, I don't Jon, I'm not a religious person.
Amazingly, the radio station was not struck by lightning.
Gillard hastened to add she was brought up a Baptist, attending the Mitcham Baptist Church. Why, she even won catechism prizes for remembering verses from the Bible.
''But during my adult life I've, you know, found a different path,'' she declared. ''I'm, of course, a great respecter of religious beliefs but they're not my beliefs.''

Meanwhile, in the USA, a 2007 poll found that 62% of respondents would not vote for an atheist candidate and there are currently no public atheists in Congress.  This article takes a look at the differences between Australia and the USA and posits several reasons for why this could happen there and not here.   First, Australia has a larger religiously unaffiliated population (31% them, 16% us) and few regular church-goers (7.5% them, 40% us).  Second, while stating her lack of beliefs, Gillard is quick to heap praise on belief and churches as positive social institutions.  And her positions are, in general, not opposed to the religious.  She is opposed, for example, to gay marriage.  And lastly, her Labor Party really only received 38% of the vote.  That was enough to put together a coalition in a parliamentary system, but would not be enough to become a President, Governor or Senator over here.  So for the foreseeable future there is little chance of someone winning high office in America without a profession, even insincere, of faith.