The President said the new positioning is not about China, but it is.

Perhaps there was one kiss too many. Suddenly, the warmth between Julia Gillard and Barack Obama transformed from being a really good look to appearing a little over the top.

Gillard did not come out with a pat line to encapsulate the alliance. But the kissing (through a couple of international conferences as well as on Obama's arrival) and the arms around each other's backs as they left Wednesday's news conference became the new version of ''all the way with LBJ''.

We are in the midst of a major realignment of American foreign policy. Obama used yesterday's address to Parliament to deliver the strongest possible line about America boosting its profile and its power in this region. ''In the Asia-Pacific in the 21st century, the United States of America is all in,'' he said. The future America seeks in the Asia-Pacific is ''security, prosperity and dignity for all . . . That's the future we will pursue, in partnership with allies and friends, and with every element of American power''.

Obama gave disclaimers that the new positioning is not about China. But of course it is about China, with that country's increasing challenge to US regional supremacy.

Australia's old fear was of America retreating from our region.

When the US seemed to be looking inward, Australia worried. But now America's stepping forward - which puts pressure on China in the short term and warns it for the future - presents problems as well as opportunities for Australia.

Under decisions announced on Wednesday, the recent American force review has led to closer Australian-US military engagement. There will be a US Marines presence in the Northern Territory for six months each year, rising from about 250 in 2012 to 2500 in 2016-17.

There has been speculation that Australia asked for this extra force on local soil. The official line is that it came out of a year-long conversation. The Americans were interested in a greater presence in south-east Asia. One source says Australia dealt itself into the US force posture review; another says the Americans ''pushed on an open door''.

A more assertive regional role by America was inevitably going to place the Labor government in a bind. It would not want to - and could not - reject it. It wants to be in the game (which also keeps it in the loop). On the other hand, Australian and American interests vis-a-vis China are, while overlapping, not always precisely the same. At least in the short term, Australia's stake is most directly economic, while the US has a broader set of concerns than the economic, despite that being absolutely critical to it.

Having decided to climb on board with a closer military involvement, the government had a limited choice, but a choice none the less. It could play up and flaunt the new military presence, or keep the rhetoric low key and perhaps settle for a more limited US force. It chose the former. When some of the government figures involved are considered, as well as the politics (the government rode the wave on the Obama visit), this is perhaps not surprising. Labor and Gillard don't want to be outdone by the Coalition on the alliance.

Foreign Minister Kevin Rudd is suspicious of China's long-term intentions and favours a ''hedging'' strategy. (It is ironic the Chinese quickly became disillusioned with Rudd's tough-mindedness, finding Gillard apparently more amenable, only to have Gillard now implement a very Rudd-like policy.) Dennis Richardson, secretary of the Foreign Affairs Department, and Kim Beazley, Australian ambassador to the US, are also strong alliance men, as is Defence Minister Stephen Smith.

Australia knows that China is and will continue to be annoyed at the troops announcement. Put bluntly, it probably doesn't care all that much. It judges the Chinese will be restrained in their reaction, and that the economic relationship is in Beijing's interest too and will not be harmed. The Chinese reaction might not be so important at the moment - although they can register their displeasure by giving a government the cold shoulder, as John Howard got in his early days. But it is a matter of how things play out longer term. If there were growing frictions between America and China, Australia's stronger military ties with the US would potentially complicate its position. (Of course in any serious clash between the US and China, Australia would always be on America's side, but foreign policy is often not so black and white.)

Opposition Leader Tony Abbott's parliamentary speech yesterday attracted some attention for being a bit ''off'', especially with its gibe at Labor over its delay in proposing to export uranium to India. He would have been better to have kept the partisanship in his pocket. But that wasn't its main interest. Abbott declared that a Coalition government would be ''happy to see the establishment of another joint facility so that these arrangements could become more permanent''. Suffice to say, the Chinese would not be too welcoming of an Abbott government.

One talking point of the Obama visit was how wavery Gillard's voice sounded when she started Wednesday's joint press conference. There was a lot of pop psychology about her apparent nervousness. The explanation was simpler. She and the President had climbed a flight of stairs. Obama had skipped up very rapidly. It's easy to get out of breath when you are trying to keep close to a fast moving big guy. Maybe there's a diplomatic message there.

Michelle Grattan is The Age's political editor.

http://www.smh.com.au/opinion/politics/gillard-goes-all-the-way-with-obamas-big-regional-push-20111117-1nl15.html