He discredits himself enormously by not releasing it. But due to the politics of the situation, only a certain percentage of political activists and commentators and citizens in general will acknowledge that fact.
Some are helping Obama to cover up his totally inexcusable behavior, others run from the issue to avoid being smeared by the MSM, and then others look at for what it is and acknowledge that Obama has something to hide, or is engaging in very bizarre, psychotic behavior.
At this point he is discredited if he does and discredited if he doesn't.