The US Presidential debate was about winning over the undecideds, not satisfying the faithful, and so Obama took the line of least resistance in many instances. Many Democratic partisans will be unhappy with the very centrist line Obama took on several issues, but the bottom line is that Obama won on McCain’s home turf which is as much as he could possibly have done – without seeming arrogant, conceited, or too intellectual.  McCain, by comparison, frequently came across as patronising: “Obama doesn’t understand” and as re-fighting yesterday’s wars.

Obama didn’t give the Republicans anything to fire up their base with and yet looked collaborative and Presidential to the independents.  Having Biden do the Democrat spin spot on CNN afterwards was masterful – who wants to hear what some paid staffer has been told to say.  Palin’s absence was commented on by way of contrast.

According to the CBS News / Knowledge Networks’ poll of undecided voters:

40% of uncommitted voters who watched the debate tonight thought Barack Obama was the winner. 22% thought John McCain won. 38% saw it as a draw.

68% of these voters think Obama would make the right decision about the economy.  41% think McCain would.

49% of these voters think Obama would make the right decisions about Iraq.  55% think McCain would.

Mediacurves.com has the figures as follows:

In other words Obama did better among Democrats than McCain did among Republicans (and there are now many more registered Democrats than Republicans) and also won by a major margin among independents.

It’s very hard to see a way back for McCain from here.  He’s had a dreadful week, and has now lost the debate on his home ground.   Next up is the Palin debate, and the economy will probably be centre centre stage for the rest of the campaign.  

Already he is over 3% behind in the statistical trend line based on all the major published polls:

<param name="allowScriptAccess" value="always"

[Update] Drew J Jones, in comments on The European Tribune noted that if certain types of polls (or certain dodgy posters) are excluded, the Margin of Obama’s lead is increased. The Polster.com graphical tool I am using to display poll trendlines allows you to filter out such polls, but for some reason beyond my ken it doesn’t seem possible to embed them in a comment. It works fine when you embed them in an actual diary – so I have added below the same chart with Zogby internet and Arg polls excluded. The impact is to expand Obama’s lead from 3 to 4% – not all that much because there are so many polls included in the chart. Each dot on the chart represents a separate poll and so a vast amount of data is included and subjected to statistical trendline analysis. Go to Pollster.com if you want to play around with this excellent tool. The graph without those polls is as follows:

<param name="allowScriptAccess" value="always"

It should be noted that Real Clear Politics, which employs a much simpler arithmetic averaging technique already has Obama with an over 4% lead in the polls. It should also be noted that, particularly with the Pollster.com methodology, the vast amount of data from many polls used screens out a lot of statistical “noise” and dramatically reduces the (typically 3-4%) margin of error of an individual poll.

[End update]

And the trend in all the key swing states is even worse:

His narrowest margin of victory in all the states he has to win in order to achieve the minimum 269 Electoral College Votes is 2.7% in Pennsylvania and there are several states which are currently in the McCain camp which are a lot more marginal than that.

But it is the overall trend which is the more important.  Virtually all of the swing states have been trending towards Obama in recent times – and this is before the events of the past week have been fully reflected in the polls.

McCain needed another game-changer tonight, and he didn’t get it.  A lot more can happen in the next 5 weeks, and I would be very worried if Obama went into the election with less than a 3% lead in the poll of polls. The Bradley effect is still an unknown quantity in Presidential elections, and recent US Presidential election results have belied the opinion polls and exit polls taken just before and after the vote.

We can all speculate as to why this might be, but a 3% margin in the polls is the very least I would be comfortable with.  Tonight’s first debate was a very good start in terms of consolidating his position.