Leading article: In the shadow of the White House

All eyes are on the US election this week, but closer to home, the by-election in Glenrothes will be important in a British context as a test of the Government's standing and of the strength of the "Brown bounce".

Weeks ago, many were predicting a reprise to the Glasgow East by-election, in which the SNP overturned a thumping Labour majority. A similar defeat in Glenrothes was being described as a possible trigger for a Cabinet revolt against Gordon Brown – the long-awaited denouement to a calamitous year for the Prime Minister.

How long ago that seems. While all bets are still off concerning the results of Thursday's vote, the tide is flowing Labour's way for now. Mr Brown must believe Labour has a good chance of winning, or he would not have risked a second visit to the seat last Friday, hammering home his message that an independent government in Edinburgh would have lacked the resources to shield Scotland from the world financial crisis.

Like the Tories, Alex Salmond's SNP has had a bad few weeks in "narrative" terms. Talk of an arc of prosperity running through Iceland has been held up to ridicule. It did not help Mr Salmond that a government minister in Oslo has asked the SNP to stop dragging Norway into arguments over Scottish independence.

But voters are unpredictable, and Glenrothes electors may yet revolt against the idea that the London establishment is patronising the Scots. If so, the SNP will be encouraged and all the old familiar question marks hanging over Mr Brown's leadership will return. After all, if Labour holds on, it will hardly rank as a political miracle. Labour held the seat in 2005 with a majority of more than 10,000, while the SNP needs a swing of 14 per cent to win. But in these febrile times, any victory achieved by Labour now – even in such a rock-sold Scottish seat – is bound to be hailed as proof of Mr Brown's political resurrection.

The final twist in the Glenrothes saga is that, anticipating defeat, Labour chose the date for the vote because it coincided with the US election. It was seen as "a good day to bury bad news". It will, therefore, be entertainingly ironic if it is a Labour win that ends up obscured by the outcome of the race for the White House.