Sen. J.D. Vance (R-OH) is demanding the Justice Department open a criminal investigation into Robert Kagan, the Washington Post columnist who wrote an op-ed warning of a potential Donald Trump dictatorship. According to Fox News, Vance is accusing Kagan of inciting “open rebellion” against the United States, for suggesting in his article, “A Trump dictatorship is increasingly inevitable. We should stop pretending,” that Democratic-controlled states might resist federal power under a second Trump term should he move to enact his controversial plans to reshape the federal government to do his bi…