According to me there are two options:
- Someone with big military power
- Someone with big amount of money to hire mercenaries/army and after that sill be very rich :p
- EVENTUALY-> Someone who is good in manipulating people to force them to spend money on army and obey his/hers orders
Of course I hope that is not going to happen, but who knows...
For now the Space Treaty prohibits all that but who knows how things will change when going to Mars wouldn't be that big of a deal and literally anyone could do it!