CHARLESTON, S.C. — It didn’t take much for Ted Cruz to bring a crowd of conservatives to its feet here. By the time the Texas Republican senator finished speaking Tuesday night, an adoring audience hailed Cruz and his no-compromise, combative style of conservatism that has made him the scourge of the GOP establishment but a hero of the tea party. “Liberty is under assault today like never before,” Cruz said, pacing the stage like a televangelist. But even in deep-red South Carolina, a well-received speech full of Cruz’s signature flair is no guarantee that the firebrand politician could win the...