The NY Times reports that the Biden administration has pulled off an amazing success in some places that will never reward him for it: America’s so-called “left behind” counties — the once-great manufacturing centers and other distressed places that struggled mightily at the start of this century — have staged a remarkable comeback. In the last three years, they added jobs and new businesses at their fastest pace since Bill Clinton was president. The turnaround has shocked experts. “This is the kind of thing that we couldn’t have even dreamed about five or six years ago,” said John Lettieri, the president of the Economic Innovation Group, a think tank that studies economic distress in the U.S. His group is releasing a report today that details the recovery of left-behind counties. Those counties span the nation but are largely concentrated in the Southeast and Midwest. In today’s newsletter, I’ll explain how they defied recent trends — including a particularly grim stretch under Donald Trump — to rebound so strongly from the pandemic recession. I’ll also show the one indicator that helps explain why voters there might not reward President Biden for the good news that has happened on his watch. These 1,000 or so “left-behind” counties suffered greatly over the past two decades under Bush, Obama and Trump, the latter of whom promised to help them and did absolutely nothing: In 2018, a colleague and I noted that left-behind counties that voted for Trump had not seen any net job gains the previous year. The…