From the opposite side of the Atlantic we watch in amazement.
The ruling Labour Party suffers one by-election defeat – a stinging one admittedly, but no more stinging than the one inflicted on George Bush's Republicans here this month in a once rock-solid Congressional district in Mississippi – and a Prime Minister who has been in office less than 11 months risks losing his head, or at least his job.
Yet Bush will remain in office, whatever happens, until next 20 January, despite a record of virtually unmitigated failure both at home and abroad. No matter that ordinary Americans are realising the damage he has inflicted on their country's reputation and moral standing. No matter that three out of four of them want him gone, or that historians have long rated him one of the worst presidents ever, if not the very worst. There's no way of getting rid of Bush before the appointed moment. Such are the increasingly evident shortcomings of that lauded exemplar of human political order, the American constitution.
Not that the jettisoning of Gordon Brown, should it occur, will be pretty. It would be a grimy little palace coup, in which the party's elected representatives decided to remove by acclamation a leader they installed by acclamation, with scarcely a nod to the views of ordinary voters.
One would like to think that Labour MPs were acting entirely out of concern for the national well-being. At least as strong a motive, however, would be the desire to save their skins at the next election. But to an extent, Brown would have been removed because he had been found wanting at his job. To which a large majority of Americans will murmur ... if only.
It may be too easy to get rid of a prime minister in Britain. You don't need a massive crisis; sometimes mere ennui will do the trick. You don't even need a declared majority of the PM's own party in Parliament – see Chamberlain (Neville) in May 1940, and Thatcher (Margaret) in November 1990.
But it is surely far too difficult to get rid of a US president. The process of impeachment stipulated by the constitution, ponderous and scrupulously fair, worked with Nixon after Watergate. But the next time it was tried, against Bill Clinton on the grounds he had sought to obstruct justice in the Monica Lewinsky affair, it descended into a partisan squabble.
Clinton's transgressions were essentially personal: who would not lie when asked if he had committed adultery? In comparison, Bush's failures have been monumental and vastly damaging to the country. A powerful case can also be made that he has violated the constitution – in the way he took the US to war against Iraq, in his use of warrantless domestic wiretapping against American citizens in the US and, above all, in his authorisation of torture and other human rights abuses against both foreign and US citizens.
But almost on the day she became Speaker after the Democrats' victory in the 2006 mid-term elections, Nancy Pelosi ruled out the start of impeachment proceedings in the House of Representatives. She knew full well that the process would be long drawn out, hugely divisive, and virtually certain to fail, given the sizeable – and loyal – Republican minorities in her House of Representatives where impeachment proceedings would begin, and in the Senate which would deliver the final verdict. She also knew that if Bush were ejected, his constitutional replacement would be a certain Dick Cheney.
George Bush may, therefore, be thankful for the US system of presidential government, and the constitutional separation of executive and legislative power. In three dramatic days in May 1940, Britain's parliamentary system could respond to the fact that Chamberlain was not the man to lead Britain in its hour of supreme need, by replacing him with Winston Churchill. Thus, albeit in less desperate times, it may yet be with Gordon Brown. America, of course, is not now facing an existential crisis such as Britain in its war with Nazi Germany. But how would it deal with one if such circumstances did arise, if the wrong person was in the White House, when an enemy was at the gate and the country did not have the luxury of a months-long impeachment process of uncertain outcome?
In a sense, the US has been experiencing a slow-motion May 1940, in which the crying need for a change at the top has been evident from the early months of Bush's second term. If America had a parliamentary system, Bush would have been out on his ear long ago – perhaps by mid-2006. But nothing could be done. You run up against that venerable and utterly immovable monument, the US constitution. For three years there has been no choice but to count the days.
Alas, the monument is showing its age. Yes, it is a marvellous construction of checks and balances, and written down for all to peruse. But these checks and balances did not prevent Bush from launching his disastrous "pre-emptive" (or was it "preventive"?) war in Iraq. Nor did the US constitution stop Guantanamo Bay, Abu Ghraib, renditions, waterboarding, CIA "ghost camps" and the rest. Britain has no written constitution; the scope for such abuses, one might imagine, would be greater. But in the "war on terror", Britain's record in terms of preserving civil liberties is clearly better than that of the US.
And while Gordon Brown teeters, the US political system, as enshrined in its constitution, generates only stasis. The country is largely paralysed, while the world too waits for America to choose a new leader.
The nomination contest between Barack Obama and Hillary Clinton has been riveting, and the general election this autumn will be no less so. But the term "lame duck" inadequately describes Bush and Condoleezza Rice as they traipse around the Middle East and elsewhere, ignored by almost everyone. There's only one thing Bush does have the power to do as these wasted months slip by – start a war with Iran.
Will the American system change? Of course not, no more than the British one will. They reflect different traditions and cultures. Both systems are set, if not on parchment, then in stone. But right now, as Brown trembles and Bush drifts on, I know which one I prefer.