Cheney's trip, planned some time ago to thank Australia for its military contributions to the Iraq and Afghanistan campaigns, comes as debate about Australia-US relations is moving to the top of Australia's political agenda.

Catalysing this is Prime Minister John Howard's recent criticism on a local current affairs television programme of the view of US Democrat presidential hopeful, Senator Barack Obama, that US forces should be withdrawn from Iraq by March 31 of next year. Howard said that this would be greeted by al-Qaeda extremists as a victory.

In Australia, critics said Howard's strong relationship with Bush had resulted in him taking a partisan position not in the interest of Australia's long-term relations with the US.

The immediate political cut and thrust in Canberra is centring on Iraq and whether Australia should maintain its 1,400 military personal there. The opposition Labor Party, rejuvenated by its new leader, former diplomat, Kevin Rudd, says there should be withdrawal in consultation with the Americans.

But the debate really is becoming a test of positions over the US alliance and security. With an election to be held by the end of the year, Howard wants to portray Labor's policy as being at odds with Australia's national interest.

"I would say the greatest current threat to the quality of the alliance would be a sense in the United States that Australia had deserted her in her hour of need," Howard says. And if the US were seen to be defeated in Iraq, the loss of American prestige and the boost to al-Qaeda linked terrorism would be harmful to Australia's interests and security.

To get some bearings on this debate, it's important to look at the nature of the alliance. To many in Asia, Australia may seem to be locked in step with the US in international relations. This is not the case. The alliance is certainly a central part of Australian foreign and defence policies. But this does not mean independent positions, if not ones at odds to US policy, are not taken. The Howard government has differentiated Australia's China policy from the US over Taiwan, for example.

From an Australian perspective, arguments for the alliance, as historian Dr Peter Edwards says in a paper published by Sydney's Lowy Institute, "Permanent Friends?", include US military aid in the event of a major threat; access to high level American policy makers; access to American intelligence; access to advanced defence science and technology; and economic benefits of access to US markets as gained under the 2005 Australia-US free-trade agreement. Associated with these is the case that the alliance enables Australia to bring US attention to its region and matters where Washington otherwise may not be concerned. It was during World War II that the foundations of the US alliance were laid with Labor prime minister John Curtin declaring that, to ensure the country's defence, Australia "looks to America, free of any pangs as to our traditional links or kinship with the United Kingdom".

While Australia continued after 1945 to maintain foreign policy and defence ties with Britain - as shown by military aid to the British forces fighting the Communist Emergency in Malaya in the 1950s and in the 1960s, the Indonesian "Confrontation" with the new Malaysia - the US was seen as now key to regional security. A product of this was the 1951 Australia-New Zealand-United States Security Treaty (Anzus). Australia's conservative prime minister, Robert Menzies, insisted on this as the price for Australia agreeing to a peace treaty with Japan. Australia and New Zealand primarily wanted insurance against a resurgent Japan. The US for its part, with the outbreak of the Korean War, saw the spread of communism as the great menace. It agreed with the treaty in order to speed the rehabilitation of Japan as an ally as well as gain Australia and New Zealand as clear allies.

Since then Anzus has provided the framework for the alliance with regular ministerial meetings and joint defence programmes. (This has been on a bilateral basis since 1986 with New Zealand's exclusion). The treaty was invoked by Howard for the first time in its history after the September 11, 2001 terrorist attacks on New York and Washington.

But there are also arguments that the benefits for Australia of the treaty can be overblown. There is no true security guarantee unlike the North Atlantic Treaty Organisation (Nato) where there are explicit mutual defence obligations. It has been described as a treaty to consult rather than to defend. In keeping with the security concerns at the time it was fashioned, Anzus's geographical focus is the "Pacific Area". The parties agree to consult if there are security threats and cooperate over defence capability. An attack on any of the signatories would oblige the others to "act to meet the common danger in accordance with its constitutional processes". The treaty affirms that it is consistent with the parties' obligations as signatories to the United Nations Charter and that they will refrain in their international relations from the threat or use of force contrary to the purposes of the UN.

Whatever the limits of the actual treaty, since it was signed more than half a century ago, Australia's diplomatic, defence, economic and other ties with the US have expanded and strengthened enormously. The US alliance has bipartisan support among the major parties in Australia. While Labor may be quite critical in opposition, reflecting in part at least the influence of its often anti-American left wing, in office it has always affirmed its ongoing importance.

But this does not mean that governments or aspiring ones can count on public support if they are perceived as subservient to the US. Former conservative prime minister Malcolm Fraser has been outspoken in this regard, writing that "the Howard-Bush relationship seems unofficially to have given Anzus a much broader scope. Australia today acts as though it is unquestioningly and irrevocably tied to support of American policy worldwide".

This week's visit then to Australia by Cheney will require some careful managing by both Howard and Cheney. While Howard may want to use this visit to argue that Rudd is weak on security, he will not want to let himself be painted as a lackey of Washington. And Cheney, considered as one of the most hawkish in the Bush Administration, will want to avoid any comments that result in him being accused of interference in domestic politics.

Andrew Symon

SINGAPORE

Australian Andrew Symon is a Singapore-based business consultant and journalist.