In comparing the motives of the crusades to the motives of the Unites States' foreign policy in the Middle East today, you could say the motivations are similar if you hold the belief that the crusades were motivated not just by religious zeal, but by a desire for cultural and regional hegemony that would lead to economic gain. In terms of tactics, further going off the idea that the crusades were motivated by more than simple piety, a parallel can be drawn between the crusades and the US's involvement in the MidEast through their use of a moral belief, in the case of the crusades the need to spread Catholocism, in the case of the US's involvement in the Middle East the need to spread democracy, to disguise a more "nefarious" motive, like a desire for cultural/regional hegemony or economic gain.
This letter was written by Leo Szilárd and signed by Albert Einstein, and sent to warn the President of US Franklin D. Rooselvelt in 1932, about Germany developing atomic bombs.
