WASHINGTON – Sarah Palin and George W. Bush won’t be in Tampa, Fla. Hillary Rodham Clinton and Al Gore won’t make the trip to Charlotte, N.C. And scores of other Republican and Democratic stars are taking a pass as their parties gather for this year’s national conventions.

The reasons are varied – and often, of course, political.

In some cases, high-wattage politicians weren’t invited to have speaking roles. Advisers to Mitt Romney and Barack Obama are selecting people to stand on the podiums who most fit the message each candidate will try to send. And who won’t steal the spotlight. Other party rock stars are choosing to be on the sidelines because they’re in hard-fought campaigns of their own.