The simplest answer for the rise in murder is that besieged police have been more cautious or ­defensive in their patrolling. This comes against the backdrop of a yearslong trend in major cities of limiting police stops and elevating progressive district attorneys ­devoted to keeping as many people as possible out of jail. The Rudy Giuliani-Mike Bloomberg approach that proved so effective in Gotham — of backing police to the hilt and aggressively working to get illegal guns off the streets — came to be considered a terrible mistake. But it doesn’t look so bad if the alternative is young men routinely getting gunned down in neighborhoods beset by intolerable chaos. If the tough-talking ex-cop Eric Adams wins and then delivers on his law-and-order promises in the Big Apple, perhaps he can show other cities how to step back from the brink of disorder. That Biden felt compelled to offer an anti-crime agenda of his own, no matter how ineffectual, highlights the political stakes.