Complex sentence: During the 2009 United Nations Climate Change Conference in Copenhagen, the NSA and its Five Eyes partners monitored the communications of delegates from different countries to give their own policymakers a negotiating advantage.
Split into simpler sentences: During the 2009 United Nations Climate Change Conference in Copenhagen, the NSA and its Five Eyes partners monitored the communications of delegates of numerous countries. This was done to give their own policymakers a negotiating advantage.