Complex sentence: Asquith's caution was not motivated solely by the need to keep the Liberal Party united: he and Grey also believed that openly backing France and Russia would make them more intransigent, without necessarily deterring Germany.
Split into simpler sentences: Asquith's caution was not motivated solely by the need to keep the Liberal Party united. He and Grey also believed that openly backing France and Russia would make them more intransigent, without necessarily deterring Germany.