Some sections of the press like to think they can make or break a government. And some politicians believe them.
It was The Sun that proudly boasted, after Labour's unexpected defeat in 1992, that it was "The Sun wot won it" for John Major.
Who backed whom in 1997
Mr Major got a taste of the same treatment before long. He was famously sensitive about the bludgeoning he took from the tabloids as his government unravelled its way to polling day in 1997.
For that contest, and after a long and controversial courtship that included Tony Blair travelling round the world to deliver a speech to a conference staged by its proprietor, The Sun - a ferocious supporter of Margaret Thatcher and enemy of all things lefty throughout the 1980s - switched to Labour.
It declared its hand early for the current campaign, coming out the day after Gordon Brown's pre-election Budget to inform the prime minister that victory on polling day was "In the bag, Tony" and he should go to the country as soon as possible.
But while it may be in the interests of newspapers and their owners to make great play of their grip on their readers, others are sceptical as to their true influence - particularly in an age of multi-channel, 24-hour television and internet news.
Unlike politicians and journalists, the population is not made up of avid regular readers of national daily newspapers. A third of voters do not read any national daily.
Nor are they loyal to one paper; they are promiscuous, switching around and so avoiding any consistent propagandist message.
What's more, where the strenuous partisan efforts of the Labour and Tory camps in the fourth estate do appear to affect voters, they mainly only counteract each other.
In the 1997 contest, according to the British Election Campaign Study, of the readers of papers that backed the Tories, 12% more voted for the party at the end of the campaign than had said they were going to at its start.
Among readers of long-term Labour-backing papers the Mirror and the Guardian, however, there was no rise in Tory support during the campaign. There was, though, an above-average rise in support for Labour.
Follow that bandwagon
Another harsh reality of the newspaper world is that it is in long-term decline, with the dailies involved in frenetic circulation battles among themselves for a dwindling pool of readers.
" If we'd backed the Tories at the last election we'd have been out of touch with our readers. If we'd backed them now, I suspect we'd have been even more out of touch with them "
The fierce competition increases the bandwagon factor. No editor or proprietor likes to be on the losing side - or on the wrong side of their readers. A paper's defection to one political party after having served its rival for years may be highly symbolic but that is not the same as being decisive.
And it is, after all, only expedient to climb aboard a bandwagon that your readers have already joined.
The Sun's own political editor, Trevor Kavanagh, acknowledged as much after his paper gave its post-Budget blessing to Mr Blair once more.
"If we'd backed the Tories at the last election we'd have been out of touch with our readers," he said. "If we'd backed them now, I suspect we'd have been even more out of touch with them."