Secretary of State Rex Tillerson arrived in Moscow on Tuesday with perhaps more experience negotiating with Russians than any new secretary of state since John Quincy Adams — whose first diplomatic mission to Saint Petersburg preceded his admission to Harvard, and who served as our young republic’s first minister to the czarist court. Tillerson needs no advice on how to deal with Moscow, but he leaves behind a country riven by arguments about Russia. Democrats are furious over interference in the U.S. presidential election, whereas some Republicans have developed a blind spot in the weather eye they traditionally train on U.S. national security issues. Reestablishing a rough consensus on principles to guide American relations with Russia, therefore, is a high foreign policy priority. Five ideas might start that process.