For years, elements of the United States Navy have visited Fremantle for R&R.
There have always been muted objections from left-wing, anti-American and anti-nuclear activists.
Their protests have increased in intensity since Australia and the United States agreed for complete crew swaps to take place during naval ship visits.
The original crew flies out after a new crew has arrived to take over.
The WA State Government supports the change as it generates more economic activity due to additional minor repairs and maintenance done by local contractors while ships are in port.
The erratic Member for Fremantle, Carmen Lawrence, opposes the development and has sought to board US navy vessels to verify that they are not carrying weapons of mass destruction.
The impending war in Iraq has exacerbated the situation with Dr Lawrence and her Green allies contending that Fremantle is now a de facto US Naval Base.
The first ship to complete a sea swap in Western Australia was the destroyer USS Fletcher bound for the Gulf.
Polls show that most West Australians support the position of the Federal and State governments.