Candidates Show G.O.P. Less United on Goals of War

DERRY, N.H. — The hawkish consensus on national security that has dominated Republican foreign policy for the last decade is giving way to a more nuanced view, with some presidential candidates expressing a desire to withdraw from Afghanistan as quickly as possible and suggesting that the United States has overreached in Libya.

The shift, while incremental so far, appears to mark a separation from a post-Sept. 11 posture in which Republicans were largely united in supporting an aggressive use of American power around the world. A new debate over the costs and benefits of deploying the military reflects the length of the conflicts in Afghanistan and Iraq, the difficulty of building functional governments and the financial burden at home in a time of extreme fiscal pressure.