U.S. Sens. Elizabeth Warren and Ed Markey of Massachusetts and Jeff Merkley of Oregon sent a letter to President Joe Biden last week calling on him to use his executive authority to issue a blanket pardon for all nonviolent federal cannabis offenders, whether currently or formerly incarcerated. In the letter, the senators, all Democrats, called America's war on drugs "failed and racist." "America’s cannabis policies have punished Black and Brown communities for too long," the…