Obama has taken steps to curb so-called oil speculation by, among other things, reducing the number of contracts hedge funds, banks and others that don't actually use oil, can hold on the commodity futures exchanges.

Obama may further tighten these and other rules if reelected. It's thought that Romney would either roll them back or not enforce them as strictly.

How much these traders influence oil prices -- if at all -- is subject to debate.

NEXT: Big Oil tax breaks