By Paul Reynolds
World Affairs Correspondent, BBC News website
When Tony Blair and George Bush meet at the White House for dinner on Thursday, they will be contemplating the beginning of the end of a relationship that has seen their policies dominate the world scene but which has also left them weakened at home for their final years in office.
In one of its perhaps less elegant wordplays, the Economist magazine declared that the two now constituted "an axis of feeble."
The two leaders have found some common ground in foreign policy
Their common cause in Iraq has not delivered the success they believed was assured.
On this visit, they will seek to justify that cause but they know that some are withholding judgement until events deliver their own verdict.
Others have made their judgement anyway.
And as the curtain prepares to come down, there are already voices being heard offstage calling for an end to the policies of intervention that have characterised the approach of both men.
A return to the past?
Former US Secretary of State Henry Kissinger recently seemed to be re-floating the old Cold War policy of containment.
In a Washington Post article about North Korea and Iran, he even challenged the very word that has come to represent the Bush doctrine - pre-emption:
Could the era of interventionist policies be at an end?
"The diplomacy appropriate to denuclearisation is comparable to the containment policy that helped win the Cold War: no pre-emptive challenge to the external security of the adversary, but firm resistance to attempts to project its power abroad and reliance on domestic forces to bring about internal change."
Perhaps echoing that, Francis Fukuyama, the man who somewhat prematurely declared an end to history after the collapse of communism, now wants a "neo-realism" to follow neo-conservatism.
And he admits it was wrong to assume that "democracy was a default condition to which societies would revert once liberated from dictators".
The future of American foreign policy beyond George W Bush is therefore being contemplated.
Not that he is going soon. He stays in office until noon on 20 January 2009.
In fact, although he could remain in his office for more than a year longer than that, Tony Blair is now most likely to go first.
Tony Blair and George Bush clicked when it came to viewing world threats
Having said once that he would serve a full term, he now concedes that he will have to leave 'ample time' for a successor to settle in.
So for him especially, it is legacy laying-down time.
Which is why Mr Blair will be giving a speech on international policy in Washington on Friday.
This speech is being compared by his staff to the one he gave in Chicago in April 1999.
That was made at the height of the ultimately successful war against Serbia by Nato over Kosovo.
It outlined a policy of interventionism that Tony Blair feels he has pursued ever since, though, as we know, he did not justify the invasion of Iraq on the grounds of a humanitarian intervention.
It is worth recalling how strongly Mr Blair supported the war against Serbia, even calling for a ground invasion of Kosovo, much to Bill Clinton's horror.
Iran's nuclear ambitions could yet shape the two leaders' legacies
He and George Bush clicked when it came to viewing world threats, and the attacks by al-Qaeda simply reinforced that.
His attitude towards Iraq should have come as little surprise and it is none now either that he seeks to defend and explain what he has done in the world.
And there is one problem on the horizon and coming rapidly into view - Iran.
Despite the interesting letter to Mr Bush from the Iranian President Ahmadinejad, the Americans still view the Iranian position with suspicion, and any attempt to engage in direct talks as a diversion from the demands of the IAEA and the Security Council for it to suspend its uranium enrichment.
Yet enrichment appears to be what Iran wants above all.
Quite how to square the Iranian circle might be the last task for the Bush/Blair axis.