Xi keeps on coming. For decades, China has limited its leaders to two five-year terms, but yesterday the Communist Party announced a constitutional amendment that would end that restriction. President Xi has already broken with his predecessors by not promoting an obvious successor during his first term in office, which ends next month. Advocates of liberalization in the Chinese establishment expressed alarm at the consolidation of power, lamenting the lack of political challengers to Xi. Congress is expected to approve the amendment March 5.