Explanation:
The discovery of oil and tin on the islands and the desire for more rubber plantations prompted the Dutch to gradually expand their control over Sumatra, part of Borneo, Celebes, the Moluccas, and Bali. Finally the Dutch ruled the whole island chain of Indonesia, then called the Dutch East Indies.
Because there needed to be legislation to rule the new country with. The Constitution was not yet written, and this was what was there instead. After the Articles of Confederation failed, the Constitution was instituted and enforced.

So an iron triangle comprises or makes the base of the policy making relation over or among the congressional committees,the bureaucracy, etc.
Hope This Helps!!!