PHOENIX — Inside a squat building ringed with a metal fence 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.
In what has become the nation’s ultimate swing county, the count here could determine whether Kamala Harris or 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 all of the ballots in Maricopa.
The drawn-out count has made Maricopa County the epicenter of election conspiracy theories spawned by Trump. It's also made it a key part of the former president's campaign to install those who supported overturning the last election into positions overseeing future ones.
But the reason it takes so long is simple. With its 4.5 million residents, Maricopa has more residents than nearly half of the states in the country and is home to 60% of Arizona’s voters. Election workers must follow voting laws - which were approved by Republican-controlled Legislatures - that slow the count. And it is one of the few counties in the U.S. that is so evenly divided politically that races are often close, so it takes longer to know who has won.
That's made the county “the center of everything," says Joe Garcia, a leader of the Latino activist group Chicanos Por La Causa.
Maricopa's position isn't just at the center of Arizona politics. The county has been a regular stop for presidential candidates as they look to clinch Arizona's 11 electoral votes — including Trump and Harris and their campaigns this year — and it is the fulcrum on which nail-biter races that can determine control of the House of Representatives and U.S. Senate pivot.


The fast-growing county also has become home to a stew of key demographic groups in the battle for the White House: a growing Latino population, retirees, younger, newly arrived voters and a broad and deep conservative population wrestling with a pivotal splinter group — college-educated, more affluent Republicans who've soured on the party's more pugnacious, and at times anti-democratic, turn under Trump.
It wasn't always like that.