"And" does not always make plural
There's a pretty interesting story in Business Week about President Bush's power to exempt companies from financial reporting requirements if they are working on top-secret stuff.
Nice work, but it's a bit marred by this sentence: Unbeknownst to almost all of Washington and the financial world, Bush and every other President since Jimmy Carter have had the authority to exempt companies working on certain top-secret defense projects from portions of the 1934 Securities Exchange Act.
That plural verb is like fingernails against a chalkboard.
Just because "and" is used doesn't automatically make it plural. "Every other president" shifts it back to singular by making the items segregable. You can think of it as an implied "or" phrase where the number of the last item controls.
Had it been written instead Bush and all presidents since Jimmy Carter, then have would be appropriate.