Governments in capitalist societies have regulated markets for centuries. The law sets the parameters in which markets operate, establishing employment laws, health and safety laws, trading standards laws and so on. Government regulation of economic activity is an essential part of any developed capitalist economy. Governments can intervene in markets to a certain extent, using their economic power to affect the allocation of resources. And, especially in wartime, governments can suppress markets, taking command of certain categories of resources and allocating them according to non-market criteria, through requisitioning, rationing and so on. But if by 'control the market' you mean directing all economic agents to behave in specific ways, then of course that is impossible, because in that case there is no longer a market.