WASHINGTON – Congressional Republicans secured enough support Friday to pass their massive tax plan, a measure that would deliver a major legislative victory to President Donald Trump and his GOP allies and make tax changes affecting nearly every American family and business. Passage appeared certain after two critical holdouts, Sens. Marco Rubio, R-Fla., and Bob Corker, R-Tenn., said they would vote for the bill next week. Rubio was the key piece of a complicated and shifting political puzzle that the White House and GOP leaders spent months trying to solve, as all Democrats vowed to oppose the bill and a handful of Republicans made strident demands. The Florida Republican insisted on an expansion of the child tax credit in exchange for his vote, and GOP leaders relented, growing a benefit for working-class families.