The senator added that the cornerstone of U.S.strategy should be the effort to shift responsibility to the Afghan people.

VOA: standard.2009.10.26

The cornerstone of this is the Nuclear Non-Proliferation Treaty, which considers only five countries as nuclear-weapons powers.

VOA: standard.2009.09.29

"It has been a cornerstone of the security of both nations, as well as the economic prosperity of both nations for almost 50 years now,".

VOA: standard.2009.09.23