https://en.wikipedia.org/wiki/War_profiteering

The government isn't something that exists above society, but is a facet of it. The MIC directly profits from wars, it pays politicians, politicians are motivated toward hawkish positions, the taxpayer is made to subsidize this. There are many other circuits discussed in the article, as concern the impact war has on the consumer market, how it's used for imperialism, etc.

Ultimately, wealth comes from labor, but the arrangement of war profiteering is extremely good at extracting wealth from labor in all sorts of ways.