What a difference a year makes. In September 2007, John McCain would have killed for the backing of former Fed chief Alan Greenspan or British PM Gordon Brown to help save his apparently doomed campaign for the Republican nomination. This weekend, neck-and-neck in the polls, he's grateful for their very
public non-endorsements. For there can hardly be better examples than Greenspan and Brown of the 'bubble reputation' well and truly pricked.

Only a year ago, Greenspan was still 'the maestro', revered by bankers, politicians and public alike. Penguin Press had coughed up a whopping $8.5m dollars for his memoirs, published on 17 September 2007 to much acclaim. "Here is a book that will sell for the next 40 years," declared the president of Penguin, Susan Kennedy.

Not likely. The paperback came out last week just as the financial world that Alan made collapsed in ruins. Lehman Brothers, AIG, Merrill Lynch – these are just some of the biggest names caught up in what The Economist is calling the 'nightmare that looks like it will never end'.

There is plenty of blame to go around, but much of it is settling on Greenspan's shoulders. "Make no mistake, Alan Greenspan is the architect of the demise of the banking system," summed up David Buik of BGC Partners on the influential Wake Up to Money programme.

"We knelt at his shrine and listened to his philosophical gems. Now he should just be very quiet." Greenspan's line was always that a property bubble could not happen and that Wall Street could more or less regulate itself. Wrong on both counts. Burned investors will be hoping he put his entire Penguin advance into Lehman Brothers shares.

Greenspan in retirement can at least throw up his hands and say: "Didn't happen on my watch". Gordon Brown has no such comfort. Whatever about the tired cliché of a week being a long time in politics, last year must seem a lifetime ago for the sepulchral premier.

Last September, he went into the Labour conference popular and respected. He had been the 'Iron Chancellor.' Through a summer of crises, he had emerged as a commanding PM. All he had to do was pull the trigger on a general election to win his own mandate. Even that month's crisis – the run on the Northern Rock bank – played to his widely-regarded strength in financial policy. Instead, he bottled the election and dithered on Northern Rock. His reputation never recovered.

This weekend, Brown goes into his party conference with the latest Ipsos Mori poll putting Lab-our a staggering 28% behind the Conservatives. Seven out of 10 voters express themselves dissatisfied with Brown. Even more ominous for Labour is that the Conservatives have broken through the 50% mark for the first time since the heyday of Thatcherism in the 1980s. Tony Blair did something similar in 1994: that ended in a landslide for him and the worst defeat for the Conservatives since the 1832 Reform Act.

Anti-Brown resignations are now working their way up the government food chain. First, it was unpaid parliamentary secretaries. This week, it was a junior minister. And the Cabinet is plotting. After a bitter meeting last week, Brown's performance was described as "bizarre" and in "a denial of reality".

More publicly, David Miliband, who impressed in Dublin last week, has already put his head above the parapet with a critical Guardian article. Now the ultra-Blairites James Purnell and John Hutton, have joined him in pointedly refusing to condemn rebels. More damagingly, Purnell says Labour's meltdown is not "about presentation, it's about policy".

The question now is who, if anyone, will have the courage to resign, as Geoffrey Howe did in 1990, to precipitate the fall of a prime minister.

Should the worst come to the worst for Brown, at least he can fall back on old friends. Back in 2006, he appointed Greenspan as an official advisor to the Treasury. Now might be the time to start thinking about tapping up the ex-Maestro for the phone number of his literary agent.

Prof Richard Aldous is head of History & Archives at UCD