The pictures of President Bush and Prime Minister Brown in London this week showed two men forcing smiles for the cameras. The two have never achieved the easy rapport enjoyed by the president and Tony Blair, and Mr. Brown is all too aware that his wholehearted backing of America in the war on terror, the war in Iraq, and the war in Afghanistan has taken a heavy toll on his popularity.

Mr. Brown, premier for little over a year, has two years before he is obliged to seek reelection, but a poll on Sunday showed how far he has slipped in the affections of the British electorate. The Conservatives attracted 47%, Labour 25%, and the Liberal Democrats 21%. Even Lady Thatcher in the darkest days of her unpopularity did not plumb such depths. Short of a miracle, Mr. Brown faces certain defeat whenever he calls the election.

When looking for an explanation for Mr. Brown’s fall from grace, a great deal has been made of his dour character. His scowling, charmless demeanor conceals an even sterner personal interior. As a son of the manse, he has always lived an earnest life of hard work and application that allows little time for frivolity.

When he obliged Mr. Blair to hand over the reins of power, at first these character traits were seen as a virtue. Mr. Blair may remain a darling in America, but in Britain he has long been a figure of derision.

Instead of concentrating, as he pledged, upon reforming the public services and enhancing state education, Mr. Blair soon was seduced by the glamour of the world stage. His eager embrace of Mr. Bush and his decision to join the alliance to remove Saddam Hussein was widely seen as an act of servitude rather than a gesture of solidarity.

As the occupation of Iraq slid into chaos, Mr. Blair was increasingly seen as out of touch with British sentiments. Mr. Brown’s principled decision to stay the course in Iraq and Afghanistan while providing British anti-terrorist agents with the tools they need to succeed has merely compounded the feeling of disenchantment the voters had for Mr. Blair. Mr. Brown is portrayed as little more than the Son of Blair minus the charisma.

On first entering 10 Downing Street at the end of last summer, Mr. Brown found himself popular for a brief time. He survived the bombs the Islamist terrorists planted to test his resolve and the electors seemed prepared to give their new leader the benefit of the doubt. Had he called a snap election, he would likely have been returned with a decent majority.

But he dithered. He asked his minions to sound out whether a surprise election would result in victory. Then, despite the universal answer that he would likely win, he froze. His consequent retreat was painted as cowardice in the face of battle and has led to a scalding onslaught from both press and public alike.

The prime minister, a student of Labour history and the biographer of the Clydeside socialist leader John Maxton, cannot fail to see in his plight a repeat of the experience of James Callaghan, the stolid Labour prime minister who followed the more charismatic Harold Wilson. Callaghan hesitated, then failed to call an election he might have won in 1978 and went down to a landslide defeat at the hands of Lady Thatcher the following year.

Mr. Brown has suffered a succession of small but significant embarrassments ever since. He has offended his own backbenchers by trying to remove the 10% income tax level that protected those with low incomes. He has failed to deliver on his promise to provide a referendum on closer European integration. He has forced through Parliament, in the face of concerted Conservative opposition, a measure to allow terrorist suspects to be detained for 42 days without trial.

The hapless Mr. Brown is on the run with the press in hot pursuit, and the electorate smells blood. As Brutus put it, there is a tide in the affairs of men and Mr. Brown finds himself up to his neck in salty water. Labour has ruled for 11 years and there is impatience and fatigue both among the voters and members of his party.

With no term limits, it is easy enough in the British system for a prime minister to outstay his welcome, as even Lady Thatcher did. Mr. Brown appears little more than a post-script to the Blair years and there is precious little he or anyone else can do to extend his tenure.

The same happened on this side of the Atlantic when George H.W. Bush succeeded Ronald Reagan and went on to rule for a single term. The identical syndrome afflicted the blighted premiership of John Major, who followed Lady Thatcher into Downing Street. It is hard to succeed a dazzling predecessor who provided clear and eloquent leadership.

There are lessons here for the presidential race. Little wonder that Senator Obama would like to portray a McCain administration as George W. Bush’s third term. By comparison Mr. Obama is a fresh face who suggests a complete change of direction.

The best chance for Labour to hold onto power is if they mount a coup against Mr. Brown this fall, replacing him with a younger, more dynamic leader the party can present as a genuine alternative to the youthful if callow Tory leader, David Cameron.

Such a practical move would inevitably be portrayed as an act of treachery in a party that prides itself on solidarity. However, as the rejection of Hillary Clinton’s candidacy has shown, often progressive parties would prefer to remain pure in thought and deed rather than do what is necessary to win an election.

nwapshott@nysun.com