1) Federalise 2) Federate 3) To change into a federation 4) To unite into a federation 5) Unify 6) Unite 1) Federalise 2) Unite 
• (v. t.) To unite in compact, as different States; to confederate for political purposes; to unite by or under the Federal Constitution.
Fed'er·al·ize transitive verb [ imperfect & past participle Federalized ; present participle & verbal noun Federalizing .] [ Confer French fédéraliser .] To unite in compact, as different States; to confederate for political pur...
[v] - put under the control and authority of a federal government