General David Petraeus backed away from uttering similar words, but it's clearly a view that holds wide currency in the U.S. military establishment: ending the Israel/Palestine conflict is a core U.S. interest that affects the safety of U.S. soldiers. Haaretz picks up (though they bury it) that U.S. Admiral Michael Mullen echoes the "linkage" argument in a document published by Al Jazeera as part of the "Palestine Papers."
Notes from a June 16, 2009 meeting quotes chief Palestinian negotiator Saeb Erekat as saying that Admiral Mullen told Mahmoud Abbas:
You're the most important person in the Middle East. Arabs and Muslims have only one thing on their mind: Palestine. So, we want to help you establish a Palestinian state... I have 230,000 troops in Iraq & Afghanistan and I am bringing back 10 each week draped in American flags or in wheelchairs. This is painful for America. Because I want to bring them back home, a Palestinian state is a cardinal interest of the USA. Washington today is different from Washington yesterday
This is the realist argument the Israel lobby goes beserk over.