I think the question should be, why?
For all the money spent what will the benefits be, other than who can piss highest up the wall bragging rights?
These are valid questions for sure,
However, There were a number of very useful inventions that came from the Apollo program which perhaps has made at least some people find use for. Such as:
Fireproof Uniforms that are now used in for Firefighters
Digital Cameras that are at least able to fit into your hands
Portable Hand Vacuum Cleaners
Vacuum Packed Food Products
Cordless Hand Tools
Quartz Clocks and Watches
Aluminium Foil
Programmable Pacemaker
Among many others such as advancements in dialysis machines.
Im not saying that a new space program could lead to a whole new wave of inventions like with the Apollo program but many household 'quality of life' and other life saving inventions came our way as a result of getting around the 'squidgy human in space' problem which exist with a human mission to Mars at present.
I think funding a mission to Mars is a far better investment than Nukes, Aircraft Carriers and Biological Weapons....