Complex sentence: It has created one major surprise where the party leader was not selected to run for prime minister this created a degree of instability with in the party, which shows the problems of using primary systems in nations where party coherence is an issue.
Split into simpler sentences: It has created one major surprise where the party leader was not selected to run for prime minister. This created a degree of instability within the party, which shows the problems of using primary systems in nations where party coherence is an issue.