to those of other nations, the U.S. spends a vast amount of money on its military. If you add in the cost of the nation's ongoing wars, the U.S. outspends every other nation in the world, combined. I'll credit Reihan Salam with being one of the few conservatives to directly address this issue, specifically for recognizing that the expenditure flows from our nation's expectations of the military and its role in the world, but that there is room for legitimate debate over that role.
Here are a couple of things that a President might not like to talk about, but has to think about. In many parts of the world, fresh water sources are being depleted. In many parts of the world, global warming threatens the food supply and will cause desertification. The drug war is destabilizing many nations, including Mexico. As things get worse in the rest of the world, it is likely that more people will attempt to illegally enter the United States. And while we can talk about measures that might be taken to reduce carbon emissions, how other countries might be assisted in developing their own economies and preparing strategies for potential food and water shortages, or how legalization of certain drugs would reduce the cash flow to drug cartels around the world, the fact is that Congress isn't prepared to take any serious action on any of those issues. Meanwhile, odds are that additional nations are going to join "the nuclear club," some of which are likely to be hit in the not-so-distant future by shortages of affordable food and fresh water.
Within that context, if you're the President, you might prefer to cut the military budget and redefine the role of the military, hoping that you can form military coalitions to address future problems. Or you might look at the future and perceive a need to maintain or even to expand the role of the military in order to be reasonably able to unilaterally defend U.S. interests as the global situation deteriorates. In that latter context, your Defense Secretary might sound a lot like Robert Gates, looking for ways to cut spending not in order to reduce military spending but to be able to maintain or expand the mission of the military without increasing the military budget. (By doing things such as reducing retirement benefits for military personnel.)
Yes, it's a fair retort, "But we could start taking steps, right now, to fix those problems or at least to mitigate their effects." But you know what? You can easily pass the military budget. You can easily pass supplemental war spending. You can easily pass a $600 billion border security bill, with the opposition party arguing "It's not enough". But when it comes to revisiting the nation's approach to drugs, carbon emissions, or whether there's an alternative to being a military hyperpower in a world that is likely to become less stable, you're likely to get Congressional consensus on only one thing: "We can't cut the military budget; if anything, we should spend more."