Containment is a geopolitical strategic foreign policy pursued by the United States. It is loosely related to the term cordon sanitaire which was later used to describe the geopolitical containment of the Soviet Union in the 1940s. The strategy of "containment" is best known as a Cold War foreign policy of the United States and its allies to prevent the spread of communism after the end of World War II.
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"The reason why Britain didn’t declare war on the Soviet Union is an
intriguing one. Unknown to the general public there was a ‘secret
protocol’ to the 1939 Anglo-Polish treaty that specifically limited the
British obligation to protect Poland to ‘aggression’ from Germany" http://www.historyextra.com/qa/why-did-britain-and-france-not-declare-war-soviet-union-when-red-army...
The Song Dynasty practiced Buddhism whereas the Tang banned the religion and persecuted those who followed it during the later time of their ruling. The Tang Dynasty also had expanded their empire and even reformed civil service. The Tang expanded and conserved their power by establishing tributary states. They had a stronger more powerful military when compared to the Song. The Song Dynasty ruled a smaller empire during their time that primarily relied on sea power. Their military power was weaker than what the Tang Dynasty’s was.
The French and Indian War. This was a war between Britain and France, not the French and Native Americans as the name suggests. The name comes from how the Native Americans/Indians allied themselves with the French.