The Illinois governor, a potential presidential candidate, is fighting the presence of National Guard troops and the activities of ICE agents in Chicago.When President Trump ordered the National Guard to Chicago last week, Gov. JB Pritzker of Illinois became the latest Democrat to bear the brunt of managing an aggressive federal government. He has concluded it must be combated with a national campaign. Aside from instructing his attorney general to file a lawsuit to block troops from other states coming to Illinois, Mr. Pritzker has few formal options to resist what he described this week as an “unconstitutional invasion of...