Entitlement spending is the bloated part of the budget now. by far.
Still they could trim some out of the defense budget.
Here is one budget item... from today -- Lockheed Martin gets a contract to sell F-35s to the military
Lockheed Martin scores $1.2B contract to produce F-35s for U.S. and foreign customers - San Antonio Business Journal
Now the F-35 they had to try out were grounded last year because well, they are crappy. The military has been decommissioning, and plans to decom more, of the A-10 the F-15, F-16 and F/A-18. The F-35 is the one jack of all trades jet they are sinking a lot of money into and according to some analysts from the RAND corp a few years back “The F-35 is double-inferior,” John Stillion and Harold Scott Perdue concluded in their written summary of the war game, later leaked to the press. The new plane “can’t turn, can’t climb, can’t run,” they warned. There were analysts from other organizations critical as well.
In looking into it tons of flaws have been found over the last 8-12 years but I do not see that all that much has been fixed. This isn't the first time we have sank a ton of money into an inferior product.
Yet about half a trillion has already been spent on development with another half trillion + tentatively to be spent over the next ~5 years.