[wdcbooks]

You raise because you want to buy the presumption that you have the best hand. You get the initiative and you get to decide when bets go into the pot.

Imagine you raise from the CO with KJo. The big blind decides to just call with KQo. You are dominated and ostensibly in deep trouble. In reality you are likely the favorite to win the hand. Much of the time no one flops a pair or strong draw. Against an average opponent your raise, and the initiative you take postflop will take down the pot.

This advantage diminishes as you move up in limits. Players do a lot more thinking about your range of hands and are a lot more aggressive in testing you. At lower limits though it is more often a fit or fold situation and the aggressor takes it down. Even at high limits the BB in our theoretical hand might assign you a range of any ace, and two broadway, and any pair. They are behind a majority of those hands and thus might fold when they miss.