Was Jefferson's embargo a failure?

I would say that the embargo was fairly successful in what
it was meant to do.  However, at the same time, it was certainly not a great thing
because of its effect on the economy.

The whole point of
the embargo was to keep the US from getting involved in the conflict going on between
Great Britain and Napoleonic France.  During the time that embargo was in effect, the US
did not go to war with either nation.  So, to that extent, it was a success.  However,
the embargo did not get either Britain or France to agree to stop seizing US
ships.

However, the embargo really badly hurt the US
economy.  So you would not really want to say that it was a good idea since the harm
that it did was so great.

So it ends up coming down to how
you define failure -- the US didn't get involved in the war so that was good.  But the
French and British did not change their policies and the US economy was hurt by the
embargo.