Richard Lugar’s loss in his Indiana Republican primary on Tuesday gave Senator John Kerry the chance to move up at least a slot in US Senate seniority. It also prompted the Massachusetts Democrat to vent anew against what he sees as increasing polarization in American politics. Lugar, who was the top Republican on the Senate Foreign Relations Committee after serving in the chamber since 1977, lost to state Treasurer Richard Mourdock, who had been backed by a Tea Party constituency.