Complex sentence: In between his terms as a councillor, Eaton served with the militia in the southern theater against the British Army and its local Loyalist tributaries, but was primarily a politician, and had less military experience than many of his colleagues.
Split into simpler sentences: In between his terms as a councillor, Eaton served with the militia in the southern theater against the British Army and its local Loyalist tributaries. Eaton was a politician with less military experience than many of his colleagues.