One of the things Gordon Brown has in common with John Major is that he is being bombarded by by-elections. We didn't have that many under Tony Blair - or at least it didn't feel like that. Possibly that was because the House of Commons had a fresh transfusion of younger blood in 1997, with the result that MPs generally were, for a while at least, in a better state of health.
But whatever the reason, if there be one at all, that's changing now. We are having a run of them. They are proving disastrous for Gordon Brown, battering him in terrible ways. The latest one, in Glasgow East, could be the worst yet. It could mark the death-knell. If Glasgow East isn't rock-solid for Labour and for Gordon Brown's Labour in particular, nowhere is. Yet even with a 13,507 majority it must be vulnerable to the Nationalists. Remember Govan in 1988.
But we should pause a moment and acknowledge that David Marshall has done a rare thing in politics. MPs don't often resign on grounds of ill-health, however impossible their condition makes it for them to represent their constituents in any meaningful way. Whether it's pressure from the Whips not to expose their Party to a costly and damaging by-election, a reluctance to give up the salary, or a simple refusal to admit what's going on with their health, the tendency is most often simply to carry on until they die or until the next general election.
Unless there's more to this than meets the eye, it would appear that David Marshall has decided not to follow the example of many before him. This by-election has come at a desperate moment for his party. But he has decided that his health makes it impossible for him to do his job properly. In wishing him a full recovery, he has done the right thing. Every constituency deserves a fully-functioning MP.