Eliot Cohen, writing in the Wall Street Journal:
Since the days of the Monroe Doctrine, American foreign policy has rested on a global system of explicit or implicit commitments to use military power to guarantee the interests of the U.S. and its allies. The current administration has chosen to reduce, limit or underfund those commitments, and the results—which we may begin to see before President Obama's term ends—will be dangerous.
Some of America's commitments are enshrined in treaties, such as Article V of the North Atlantic Treaty, which says of NATO's 28 member countries that "an armed attack against one or more of them in Europe or North America shall be considered an attack against them all." Other commitments are less formal. The U.S. has no defense treaty with Israel, but repeated presidential declarations, including those Mr. Obama will make during his trip this week, amount to nearly the same thing.
Some commitments are moral and humanitarian, such as the "responsibility to protect" that led American decision makers racked with guilt over the Rwanda massacres of 1994 to intervene in the Yugoslav civil war in 1998. All amount to a web of obligations that have been central to the American role in the world since World War II.
Over the past four years, the U.S. has scaled down its presence, ambitions and promises overseas. Mr. Obama has announced the end of the early-21st-century wars, though in truth the conflicts in Iraq, Afghanistan and elsewhere are merely shifting to new, not necessarily less-vicious phases. He has refrained from issuing unambiguous threats to hostile states, such as Iran, that engage in bellicose behavior toward the U.S., and he has let his staff speak of "leading from behind" as a desirable approach to foreign policy.
Whole thing here.