Oh, yes there is.
Those who vote for him or could potentially vote for him believe he was born in the U.S. or could give a rats ass and see "birthers" as a bunch of loonies.
As long as his opponents look and act like loonies, he wins.
If he were to produce evidence which would satisfy "birthers" then he looses a wacko opponent group. That would not be smart politics.
So the status quo is the best for both sides. Keep doubt about his legitimacy on our side (which is good for the base) and the left gets to see what it wants to see - which is good for their base.
One problem with that.
As the nation gets taken over by thugs, eventually more and more people will see that the rule of law is not a fringe issue, and the people who have been demanding it.... are the only people you can trust.
Okay. Two problems. The other:
The Hawaii DOH has indirectly confirmed in 2 different ways, through official communications, that the COLB Obama posted is a forgery. Not a good idea to commit a crime in order to make your opponents look crazy. Eventually the truth will come back and bite you in the butt.
You left out the one group which tilts elections one way or the other - INDEPENDENTS. Neither hard core left or hard core right.
By continuing to conceal his birth certificate, Obama is LOSING the Independents. They see a problem because everytime they get a drivers license or sign their kid up for some extracurricular activity they have to produce a birth certificate. Trust me I know - my family is filled with independents and most of them are now birthers.
And THAT is not smart politics, no matter how much you may wish it to be so.