On his last day as U.S. Defense Secretary, Robert Gates told Reuters that defense spending is not the cause of a soaring budget deficit and warned against disastrous cuts.

President Barack Obama has called for the U.S. Defense Department to pare $400 billion from its budget over the next 12 years and Gates two years ago made budgetary efficiency a central goal, enacting cuts projected to save $154 billion over 5 years. He said it was partially a response to the political reality as both Republicans and Democrats sought ways to reduce government spending.

I saw this train coming and knew we were going to have to get better and more disciplined if we were going to ... defend ourselves at all, Gates said. We had to be seen as out in front in trying to do smart things to make this place more efficient and more cost-effective.

During his tenure Gates acknowledged that the U.S. military would need to restructure its budget as it became more likely to face a reduced role in years to come. But he noted that even a drastic cut of 10% of the Defense Department's budget would only shrink the deficit by about 4%, or roughly $50 billion.

We are not the problem, he said.

President Obama surprised Gates Thursday by awarding him the Presidential Medal of Freedom, the highest honor a president can bestow upon a civilian. It was an unexpected occurence for Gates, who joked that should have known the president was getting pretty good at this covert ops stuff.