The ads on Facebook sounded populist and passionate: "The people are rising up against these insane shutdowns," they said. "We're fighting back to demand that our elected officials reopen America." But the posts, funded by an initiative called "Convention of States," were not the product of a grass-roots uprising alone. Instead, they represented one salvo in a wide-ranging and well-financed conservative campaign to undermine restrictions that medical experts say are necessary to contain the coronavirus - but that protesters call overkill and whose economic fallout could damage President Trump's political prospects. A network of right-leaning individuals and groups, aided by...