Complex sentence: This underscored much of the ideological problem facing Bukharin's supporters in that they lacked a political space of their own as their ideas had little to differentiate themselves from social democracy and provided little reason for them to have an independent existence.
Split into simpler sentences: This underscored much of the ideological problems facing Bukharin's supporters, in that they lacked a political space of their own. Their ideas had little to differentiate themselves from social democracy and provided little reason for them to have an independent existence.