What a pleasant surprise! I thought this would be another pro-centrist diatribe against Bernie similar to the evidence-free rants of Chris Crawford.

Two recent elections support your theory: Jeremy Corbyn’s loss in the UK, and the US 2016 GE. In 2017 Labour won on a leftist platform, but particularly by upholding the Brexit referendum results. Labour was expected to lose this time. Corbyn’s turn away from Labour supporters on their biggest issue — Brexit —resulted in an historic lose to the Tories. In 2016 Bernie had the biggest crowds of all candidates prior to the D convention. He was lucky to fill a small gym by the time he finished his marathon campaigning for Clinton (not just by the way, Bernie did nearly more than 3 times as many rallies for Clinton as Clinton did for Obama). It is the messager but much more the message that gets people off their couches.

“Pivoting to the center” after the nomination just tells voters, “Either I was lying to you before, or I’m lying to you now.” Sanders is the most popular politician for a reason — he doesn’t pivot. When he wins the nomination it would be very good for him to remember that, and the correct lesson of McGovern you describe so well.