Ongoing battles about the validity of using “nationwide injunctions” to protect third parties from allegedly unlawful conduct by the government — in appeals from decrees that blocked the Department of Justice from withholding congressionally budgeted funds as part of the Trump administration’s attempt to muscle municipalities into cooperating with its deportation program — inspired professors across the country to examine the “lost history” of decrees that were so extensive they used to be referred to as “omnibus” and …