Anyone have a spare nail?

For want of a nail, the horseshoe was lost
For want of a shoe, the horse was lost
For want of a horse, the soldier was lost
For want of a soldier, the battle was lost
For want of the battle, the war was lost
For want of a war, the Kingdom was lost

(Small things can make a big difference - never underestimate your importance in the grand scheme of things :) )