Even in less turbulent times, there is an endearing unreality to the State of the Union address delivered early each year by the US president to the congress.

Every January or occasionally February, politicians who have spent the last twelve months accusing each other of just about everything from treason to pederasty (literally in the current case), nod solemnly and applaud loudly when the president speaks movingly of the power of bipartisanship to get the nation’s business done.

Whatever traumas may be going on outside – war, pestilence, Depression, the wounded , angry complaints of insulted American Idol contestants - the president stands before the congress and the nation and says the state of the union has never been better.

Then, with even more commendable chutzpah, he goes on to adumbrate a list of demands for legislation that congress must enact if the country is not to collapse – a list, that in all but the most favourable of political circumstances, stands only the slimmest chance of success.

That feeling of unreality was heightened last night when Mr Bush delivered his sixth State of the Union. Of course the president was trying harder than ever to play his constitutional role as head of state, of uniter, not divider. With his approval ratings near all time-lows, Mr Bush’s was keen to reach out as far as possible into the centre-ground of politics. But still it was hard to escape the sense that the Capitol Building last night had entered a sort of parallel universe.

First, Mr Bush was speaking for the first time to a congress controlled by the other party, which means he could have proposed the enactment of a compulsory national diet of motherhood and apple pie and it would stand absolutely no chance of success.

Having won control of congress for the first time in 12 years Democrats are already in the process of legislating their own agenda. And though Mr Bush did his best to dress up his main proposals – tax cuts and a balanced budget, energy conservation and health care reform - in the most attractive garb possible, he has about as much clout now with the legislature as a senior staff member on a Senate committee.

Second, there was a strangely familiar, one might even say iterative quality to most of the speech. The centerpiece domestic policy proposed – a shift in energy consumption to reduce America’s dependence on imported oil – has been the stated goal of just about every president for the last 35 years. Measures to broaden the reach of health insurance also seem to have been an objective of every president in living memory. And yet the number of those who are uninsured does not seem to change much from one decade to the next.

But above all, there was a palpable sense last night that the State of the Union was not really about the state of the union, that the fate of the country’s current course will be determined not by the panjandrums assembled in the House of Representatives last night but by American troops engaged far away and by ancient religious hatred and sectarian strife among barely pronounceable peoples.

The president had already scooped his big speech earlier this month when he announced his plan to send more troops to Iraq in a last ditch effort to win the war. Against that all-consuming, contentious and consequential decision, everything else is mere furnishing.

Mr Bush, of course, repeated the main aim of his new strategy last night and Democrats listened politely to some bromides on the war on terror and the importance of victory in Iraq. But behind the courtesies and the expressed unity of purpose, the battle that now rages over the conduct of American foreign policy will not pause to recognise the rituals of the political calendar.

The war in Iraq – and what may yet be done in Iran – will dominate not only the politics of this congress and next year’s presidential election but perhaps the course of American history in the next decade or more. Either America’s fortunes will turn around thanks to the new strategy and history will look anew at the disastrous course of the last few years. Or the surge will fail and the collapse of Mr Bush’s final gamble will produce a political reckoning of unknown scale and consequence.

For Democrats, and a growing number of Republicans the challenge is how to oppose a policy they disagree with, without seeming to undermine America’s unity behind its troops.

Nothing more starkly illuminated than the moment in Mr Bush’s speech where he urged congress to support his new strategy.

"Our country is pursuing a new strategy in Iraq – and I ask you to give it a chance to work. " he said, to silence from all but some of the Republicans in the chamber. Then as he added quickly, "And I ask you to support our troops in the field", the entire audience, Democrat and Republican stood as one.

The biggest challenge for any president kicking off his final two years in office to is to stay relevant to the national political conversation.

The challenge is dramatically heightened when, as now, a president faces a hostile and newly emboldened congress, when the race to succeed him is already well under way and when his approval ratings are at bottom-fishing lows.

But oddly, irrelevance is not Mr Bush’s problem now. His fateful decision on Iraq ensures at least his relevance to American politics until the very end of his term. If he fails, his anguished and wounded Republican Party will fondly wish he had been much more irrelevant.

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