Assertion: helicopter | /r/CapableOf | prompt the u.s. military
Facets:
value: to change its defensive strategy
type: PURPOSE
Source sentences:
text: The helicopter was effective, and prompted the U.S. military to change its defensive strategy in Europe by blunting any Warsaw Pact advance with anti-tank helicopters instead of the tactical nuclear weapons that had been the basis for NATO's battle plans since the 1950s.