We may not know the next president on Election Day. This Arizona swing county could be why [Video]

Inside a squat building ringed with a chainlink fence and concrete barriers in downtown Phoenix, election workers on Nov. 5 will begin a grindingly slow tally of every ballot cast in the vast expanse of stucco and saguaro that is Maricopa County, Arizona.In what has become the nation’s ultimate swing county, the count here could determine whether Democrat Kamala Harris or Republican Donald Trump will be the next U.S. president. It also is likely to determine the winner of a closely watched race that could decide which party controls the U.S. Senate.It is one of the most consequential battlegrounds in the country. That means voters, campaigns and people around the world sometimes must wait more than a week to learn who won the county, and with it, statewide races in the swing state of Arizona. This year, election officials warn it could take as long as 13 days to tabulate …