Complex sentence: The 26th Airborne Battalion proved politically unreliable, and in 1980 they initiated a rebellion against the PDPA government, the Commando Brigades were, in contrast, considering reliable and were used as mobile strike forces until they sustained excessive casualties.
Split into simpler sentences: The 26th Airborne Battalion proved politically unreliable, and in 1980 they initiated a rebellion against the PDPA government. The Commando Brigades were, in contrast, considering reliable and were used as mobile strike forces until they sustained excessive casualties.