Complex sentence: As the war progressed, southern influence weakened, and the northern grip, both military and politically via the Lao Dong Party, was strengthened, a development lamented by some former VC personnel who were forced off the stage by the northerners.
Split into simpler sentences: As the war progressed, southern influence weakened, and the northern grip, both military and politically via the Lao Dong Party, was strengthened. This development was lamented by some former VC personnel who were forced off the stage by the northerners.