After 21 months, Beyonce announced yesterday that she will no longer star in Clint Eastwood's adaptation of "A Star is Born," citing schedulng conflicts.   BUT, giving this a little thought, we all know that Beyonce and husband Jay Z are big supporters of President Obama, so is it really a scheduling issue, or was it the poor timing of Clint Eastwood's appearance at the Republican National Convention, speaking at length to an empty chair meant to represent the President?  IJS