It really shouldn't be very surprising. Every time we are in a major long term war, unemployment goes down. We need people to build new planes, bombs, bullets, guns, rocket, trucks, etc. I'm not sure it is worth the exchange. Add in the number of people working to rebuild the Gulf Coast and it all makes sense.
But, I do agree with Blackadder that a President has very little to do with the economy or unemployment rates. That is of course unless he does something to hurt it, i.e. Clinton's crusade against Microsoft or appointing the wrong head of the Federal Reserve. IMO, the only thing a President can do in regard to the economy is hurt it.