Final answer:
Senator Beveridge's speech supports a combination of political, economic, and cultural causes for imperialism, highlighting governance, trade, and American exceptionalism.
Step-by-step explanation:
The speech excerpt from US Senator A.J. Beveridge illustrates a blend of political, cultural, and economic causes for imperialism. Politically, Beveridge suggests America has a divine mission to administer government to 'savage and senile peoples,' which reflects the political motive of spreading American governance. Economically, Beveridge implies imperialism is beneficial as it provides markets for American goods, particularly stressing the economic relationship with Asia after mentioning 'our largest trade henceforth must be with Asia.' Culturally, the speech evokes the idea of racial superiority and a sense of American exceptionalism, which represents the social and cultural justification for empire-building during the era of imperialism.