c onclusion 353On occasion, circumstances may briefl y grant a president greater lat-
itude. When the nature of a confl ict changes, a president can revisit
some of his initial decisions. Lincoln did so when he decided to turn
the Civil War into a struggle against slavery in the South—the shift
opened an opportunity to pursue a hard war against the social and eco-
nomic foundation of the Confederacy. Even then, however, the loss of
agency resumes, and a president becomes bound by his second round
of core decisions. Recall that in 1864, at a low ebb in Union fortunes,
Lincoln considered a compromise peace with the South, one that would
have forced him to revoke the Emancipation Proclamation. To do such
a thing, he realized, would undermine the moral foundation of the
North’s cause and shatter his political coalition. Emancipation remained
his policy. Sometimes, too, battlefi eld developments will place new
tools in a president’s hands. Military commanders on the ground in
Iraq devised counterinsurgency methods unknown at the time of the
2003 invasion. But the gain conferred by an operational or tactical
innovation does not reverse the broader trend toward reduced agency,
as evident in the narrow scope of choice available to Bush by late 2006.
A new president who inherits an ongoing war also may regain dis-
cretion, at least if he has avoided committing himself to a policy before
reaching the White House. Nixon, who pledged to seek “peace with
honor” in Vietnam, had wider (but not unlimited) options in 1969 than
Johnson did at the end of his term. Obama found himself with an
opportunity to redefi ne the goal of military intervention in Afghani-
stan. Here, too, an incoming president discovers that his window to
shape the war opens for just a few moments, because his choices will
quickly limit his subsequent options. In Vietnam and Afghanistan
alike, the decision to begin disengagement served as a clear signal to
other governments that the U.S. military would depart sooner rather
than later, with a concomitant decline in the president’s capacity to
shape their behavior.
Th e Next Wars
In time certain trends seem likely to impose restraints on the capacity
of presidents to initiate a war. Th e United States for the moment enjoys
a rare position of global military supremacy. This will not persist