Complex sentence: In terms of size, Solano López's 30,000-man army was the most powerful in Latin America but the army's strength was illusory because it lacked trained leadership, a reliable source of weapons and adequate reserves.
Split into simpler sentences: In terms of size, Solano López's 30,000-man army was the most powerful in Latin America. But the army's strength was illusory because it lacked trained leadership, a reliable source of weapons and adequate reserves.