History -- 19th Century -- 1 20th Century -- 1 Colonies -- 1 Commerce -- 1 Congresses 1 Congresses -- 1 more ... Defenses 1 Economic conditions -- 1 Industrialization -- 1 Information warfare -- 1 Military art and science -- 1 Politics and government 1 Politics and government -- 1 Regionalism -- 1 Sources 1 World politics -- 1 less ...