But they can have the opposite effect. I'm remembering another Prime Minister suffering economic difficulties, with high unemployment, high inflation, and record low poll ratings. Mrs Thatcher (for it is she) looked doomed against her smooth young public-school opponent, Michael Foot ;-)
Don't mock. By 1982 Mrs T was so far behind in the polls that even Footy only had to avoid clangers to stay well ahead. The next election was his to lose, not Thatcher's to win.
Then General Galtieri invaded the Falklands. The fact that the trigger for the invasion was a penny-pinching act of her own government (the announcement by Defence Secretary John Nott of the proposed withdrawal of the only British naval vessel in the South Atlantic, HMS Endurance) was forgotten. Her response to the invasion, and the success of the task force, sent her popularity soaring.
Three weeks ago Gordon Brown was the most despised man in Britain. The Right hated him for his gargantuan waste, the abolition of the 10p tax band, his destruction of private pensions, his utter uselessness. The Left hated him for PFI (as did some of the Right), ID cards, the abolition of the 10p tax band, bankrolling Iraq and Afghanistan (although not with a big enough wad to give our soldiers decent kit), his utter uselessness. Everyone else hated him for his utter uselessness. Everything he touched turned to dross.
Then the Great Economic Disaster of 2008 struck as a whole cloud of securitised-debt chickens came fluttering home to roost. But it's done Gordy a lot of favours - despite the fact that GB, as Chancellor for ten years, is implicated up to his neck in whatever dodgy debt fantasies the City's accountants dreamed up to keep the bottom line looking good. Who was in charge of regulation ? Who prided himself on the 'light touch' of the FSA ? Who was the guy who knew it all ?
a) a lot of the lefties have stopped lambasting him to focus attention on their old enemies, the bloated plutocrats. This may not last.
b) said lefties are suddenly chipper at the sight of Big Capital calling for state intervention and the perceived collapse of capitalism. Just when they'd pretty much given up on any such thing happening.
c) conversely, the free-marketers are depressed to a greater or lesser extent. The American disaster has dampened their ardour. To be fair, this has been a Big Week. Tectonic plates have shifted, and the deregulated - or specifically, credit deregulated model of capitalism looks fatally compromised. Good. Doesn't of course, do anything about the long-term, structural disasters - education, demography, welfare dependency - which, more than any amount of creative asset pricing, spells our decline.
d) being 'the man in charge' at a time of crisis will always mean that people tend to rally round you. Bush may need (a Democratic) Congress - Brown has still a tame PLP, with a hefty majority, to do his bidding.
e) the Tory Conference has been overwhelmed in the news by the financial hurricane. In vain Mr Cameron offers to help the Government. As seen above, Gordon don't need Dave's help. The expected 'conference bounce', when the Leader is all over the news bulletins for a week, may not materialise.
f) having something to worry about other than what two public-school bullies (I'm trying to put myself in his Oxfords) will be throwing at him each Wednesday can't but do him some good.
Of course, I still want him out asap. But what will the man being beaten up by Somali youths on the top floor of the Clapham omnibus think ?