As the history of the twentieth century has shown, states love a good war. Like spoilt children, the mildest irritation is used as an excuse to invade, bomb and plunder other states. And where no real provocation exists, states will invent them. Sometimes for states wars entail considerable risks, they might lose. Far better to pick on some weaker state where victory is assured as in the ongoing bombing of Iraq.
Victorious wars have many advantages for states.
They increase power and domination over other states. They bring in wealth for the state and it's capitalist allies. They strengthen support from the masses - everyone wants to back the winning team. But sometimes things go seriously wrong, as happened most dramatically in Russia in February 1917. Incompetent generals, massive defeats, shortages of food and galloping inflation all fuelled massive popular discontent and, ultimately, spontaneous revolution.