Elections are often talked about using military metaphors.  There has been much talk this week of “first shots fired” and so on.  People talk of advance and retreat, parties wielding their big guns.

I prefer the American metaphor of the race.  Elections are indeed a race, but not a sprint.  Think more the 10k or the marathon.  It’s not the first person out of the blocks who necessarily wins.  The race is about stamina, staying power.  It requires endurance but is run with your head as much as your feet.  There can also be unpredictable twist and turns that hurt you and which you never saw coming.

This was the metaphor that came to my mind as I watched David Cameron stumble over tax policy on the day of his big launch.  We had been told this was the time the Tory campaign would really begin.  There were posters, a press conference, a draft manifesto. Money and time had been spent.  Journalists were called, blogs prepared tweets at the ready.

The poster said something along the lines of  “I’ll cut spending but I’ll spend more” which didn’t seem the clearest message to me anyway but the bigger message was the Tories had started and this was the answer to critics who said they had been vague on policy.

Then the leader put his foot in it.  Not just a slight misstep but a great big stamp, like a kid trying to make the biggest splash in the puddle that he can.

The poster was right in a sense because the tax question exposed the huge contradiction at the heart of all this – promising to go further, faster, harder on the deficit and promising tax cuts which cost money at the same time.  When confronted with this Mr Cameron acknowledged the problem and said the tax pledge (on married couples) wasn’t really a promise anyway, merely something that would be nice to do.

Then the flip flop.  The leader had misspoke.  New words were issued.  It was a promise after all.  Contradiction restored.  For one audience, promise to cut the deficit, for another, promise tax cuts.  No one knew what had been said that morning now.  Just that confusion reigned and Tory tax policy was about as sure of its direction as Rab C Nesbitt at five to midnight on New Year’s Eve.

Does this matter?  Isn’t it just the usual political argument?  It does matter.

It shows that when the Tories finally started talking policy, they got into an instant mess.

That instant mess is a result of not having thought through the policies in the first place.

The trouble with the Tories is they have misread the New Labour experience.  They think it was a PR trick, thought up by Tony Blair and a few others.  Tell a few people you’ve changed, don’t worry about policy, just redo the logo.  But that doesn’t work and isn’t what the modernisation of the Labour Party was.  It was about substance, about really changing, about thinking things through.  It meant being able to take a different stance on critical policy issues like public services, Europe, defence and management of the economy.

And this matters for the public because the Tories hope to be the next Government, indeed many of their MPs assume they will be before a single vote has been cast.

As I said, it’s a marathon, not a sprint, and I wouldn’t want to read too much into the first 100 metres.  But the Tories have stumbled, and stumbled in an important way.  There are many more miles to run.