The nation’s largest police union, along with its Chicago chapter, has endorsed Republican President Donald Trump’s reelection bid, potentially helping to boost his law-and-order message. While the endorsement might have been expected, it further illustrates a division between law enforcement and protesters who for months have railed against police brutality and called for racial justice after the killing of George Floyd at the hands of Minneapolis police. The endorsement isn’t likely to hold much sway for Trump in heavily Democratic Chicago, but John Catanzara, president of the local FOP and an outspoken Trump backer, is happy to antagonize the likes...