Complex sentence: By December, the movement had grown to the point that Eisenhower had his friend Clifford Roberts secretly organize a political advisory group of close, trusted persons to watch it, and as momentum behind Taft's candidacy grew, Eisenhower's reluctance to run declined.
Split into simpler sentences: By December, the movement had grown to the point that Eisenhower had his friend Clifford Roberts secretly organize a political advisory group of close, trusted persons to watch it. As momentum behind Taft's candidacy grew, Eisenhower's reluctance to run declined.