That is how I will probably feel if Obama/Dewey doesn’t defeat McCain/Truman. I think that the polls predicting an Obama victory coupled with the anecdotal evidence (the huge crowds in Obama’s rallies) and magnified by the pro-Obama bias of most leading journalists and pundits, have contributed to the current conventional wisdom that an Obama win (perhaps even a landslide) is inevitable.

An interesting analysis in the Times of London doesn’t challenge this conventional wisdom as much as it tries to put it in some perspective. In addition to the so-called Bradley Effect, it discusses the impact of the so-called spirbal of silence:

The first is that American pollsters have not yet experienced what happened here in 1992 – when the polls pointed to a Labour victory but John Major won. The conventional wisdom is that 1992 was great for the Tories but terrible for the pollsters. In the long run, the opposite turned out to be true. Victory in 1992 turned to ashes for the Conservatives, whereas the pollsters used the debacle to get themselves sorted out.

Now British polls are properly and carefully weighted, taking account of what is known as the spiral of silence – the tendency of voters for the less fashionable party to keep their intentions to themselves. British pollsters weight their results to allow for these shy voters. US pollsters do not.

It isn’t unreasonable to believe that there could be a Republican spiral of silence. And that US pollsters are all missing it.

There is some evidence of mistakes among US pollsters. Every poll has a margin of error, to take into account the fact that a limited sample has been consulted. But the website fivethirtyeight.com has shown that during the primaries there was on average a 2.3 per cent pollster-introduced error, caused by poor methodology. This is not the case in Britain.

Maybe. But then there are also trends that suggest that the pollsters are underestimating the support for Obama:

The other ones suggest that the pollsters may be underestimating, not overestimating, Obama.

In an election where only 60 per cent may vote, all pollsters have to weigh their findings to reflect how likely respondents are to cast their ballot. The difficulty is deciding how. Usually pollsters use previous elections to help them to decide who is going to vote. But what if, in this election, different sorts of voters are going to turn out?

There is reason to believe that young people and African Americans will turn out for Obama as never before. Some pollsters are adjusting for this, others are not (hence some of the variability in the polls). The result will depend to an extent upon who is right about this.

A second unknown is the use of mobile phones. A segment of the electorate – on the whole younger, poorer people – no longer have land lines. Yet pollsters use random digit dialling of landlines to build their samples.

Some say that this undercounts Obama support by 2 or 3 per cent.

So is it possible that these trends and counter-trends will cancel each other? Your guess is as good as mine.

In any case, there are many reasons why I don’t want McCain to win. I’ll now add the danger of the gloating by you know who to the list.  

UPDATE: Difficult to argue with Karl Rove and almost everyone else that Obama will win very big. If they’re wrong, we’ll also have to kill all the pundits!