Complex sentence: The organization started as a moderate group which aimed to privatize and modernize Seattle's transit systems but it later became the leading think tank of the intelligent design movement, with Gilder writing many articles in favor of ID and opposing the theory of evolution.
Split into simpler sentences: The organization started as a moderate group that aimed to privatize and modernize Seattle's transit systems. It later became the leading thinktank of the intelligent design movement, with Gilder writing many articles for intelligent design and against the theory of evolution.