Despite an apparent strategic & social comfort which the USA and Australia seem to share, it's essential to recognise some key differences, i.e.

* great contrasts in size & strength of the two nations - it may be generalised (see statistics) that Australia is unlikely for any US government to merit more than 4 minutes per hour (or 1.6 hours per day) of their attention or interest - despite the head-patting paternalism accorded to visiting Australian prime ministers in Washington DC

* perceptions of an American 'manifest destiny' to serve as a model for other countries - and a right to influence those countries to imitate an American model & its virtues ... (read further note on this, from Joyce Carol Oates)

* displayed religiosity in America - to those Australians comfortable with rational and secular governments, responses to the "sleeve Christianity" of American society and politics range from amusement to revulsion ... (read further note on this, from Mike Moore)

* irrational fear and anger of US citizenry at their own governments, at initiatives like universal healthcare, (expectation of services but) inability to accept taxation increases to fund them - preventing measures to reduce swelling government deficits ... (Bishop John Shelby Spong comments, on these tensions )

There are also debates within Australia, on the extent to which Australia's defence needs & strategies match or differ from those of the USA ... (read on the alliance within May 2009 Defence White Paper, as a stated government viewpoint)