Player Military Power is an indicator of power. There are four different Military Powers, White (the one players start out with), Bronze, Silver and Gold Military Powers. Your Military Power increases your Attack Budget and it depends on several requirements:

Military Power Resources WWO-Influence Bases/Resources Military Rank
Bronze - - - 25
Silver 5.000.000 1.500 60 -
Gold 15.000.000 6.000 80 -

P.S.: You only need to meet one of these requirements for your Military Power to increase. This means that if you have 50 Resource Bases/Workers and 300 WWO-Influence in Supreme Units but you have 7 Million Resources in Normal Units, your Military Power will be Silver.