Complex sentence: Roosevelt still continued to object to the "Happy Warrior" speech, and only begrudgingly relented to recite it after Al Smith intervened and issued him an ultimatum to either deliver the "Happy Warrior" speech or deliver or nothing at all.
Split into simpler sentences: Roosevelt still continued to object to the "Happy Warrior" speech. He only begrudgingly relented to recite it after Al Smith intervened and issued him an ultimatum to either deliver the "Happy Warrior" speech or deliver or nothing at all.