oil wars are (and can be) waged only and only if the cost of war, blended with the cost of oil that is procured by means of that war is not prohibitive for the functioning of the cycle of production-consumption -profit-reproduction. in proper capitalism, the only indispensability is profit that preferably occurs in the far more controllable and predictable ambiance of freedoms and competition. therefore, no component of the whole production-consumption-profit-reproduction cycle, financing, raw materials etc., even oil can be allowed to take hostage the whole process. according to many authors, though, oil, especially when used as a political leverage by otherwise politically ineffectual world players, tends to upset economic balances.
a) oil needs to be replaced by other forms of energy. major oil companies and energy giants are already investing billions of dollars on alternative sources that are replenishable and also environmentally sound. a breakthrough is imminent (*).
b) the bulk of oil revenues from petroleum exporting countries are either politically squandered (mostly, if the government is anti-western and anti-u.s.) or invested in western businesses by oil sheikhs etc. this means that a drop in the popular consumption of oil is far more of an economical risk for producers than its prices falling. you cannot fetch a price for something that is virtually worthless.
c) by the same token, too expensive oil also means too expensive everything. it means people will simply consume less of everything and the whole global economic scheme will simply shrink, along with profits. in that case, those with only oil to sell, will suffer far more losses than the rest as they will have more need and less money for things that make their world go round.
c) in the shorter run (j. maynard keynes said "in the long run, we're all dead", anyway), panic boosts in per barrel prices of oil, are not impossible. many industries and economies are going to be affected and perhaps sink as a result. however, just like in practice, the recent mortgage crisis mainly helped weed out the uncompetitive, unyieldy volume of credits in the global (especially american) market, possible per-barrel-crises too, will eventually strengthen the structure of capitalist world economy; and subjugate the technologically less advanced and backward raw-material-vendors. countries and societies that tend to act like badly managed business enterprises and those who fail to manage the transition to competitiveness, will end up poorer or bankrupt. if they are oil exporters only, they will have even less of a control over their global fate.
d) those fallen powers will produce the rogue states of tomorrow.
this is a short read from the globe's coffee cup. for now though, stains do not waft the sweet smell of fresh coffee but the rank odor of crude.
(*) i find no reason to succumb to the conspiracy theory that feasible alternatives are already developed but kept secret because economies are too geared to fossil fuel consumption. the world's primary energy is electric and it can be produced from many alternative sources without disrupting the petrol based industries though cutting oil prices down to logical levels.