Complex sentence: Cliff also backed Haston when he disputed the growing sympathies of the FI for Tito's Yugoslavia, but by this time Haston was growing demoralised and would soon drop out of revolutionary politics entirely.
Split into simpler sentences: Cliff also backed Haston when he disputed the growing sympathies of the FI for Tito's Yugoslavia. But by this time Haston was growing demoralised and would soon drop out of revolutionary politics entirely.