President Joe Biden’s black voter base is dwindling. Whether it’s because of his handling of the Israel-Hamas war, the enormous economic strain forcing many Americans to take on additional shifts or second jobs, or even his push to ban menthol cigarettes, black Americans are taking a second look at the Democratic incumbent. What this means for Biden in the 2024 election is clear. Even the smallest falloff in a constituency long dominated by Democrats could spell disaster. It’s leaving the door wide open for former President Donald Trump, who won 8 percent of the black vote in 2016 and then 12 …