Senators Ted Cruz and Marco Rubio mounted all-out efforts to topple Donald Trump in the war for the Republican presidential nomination, seeking to steal support from the billionaire frontrunner in South Carolina — and each other. The state holds its crucial Republican primary on Saturday, and Trump is seeking a comprehensive win that would boost his claim that he is pulling away from his rivals, notably the two first-term senators eager to rein him in. "This race will be decided friend to friend, neighbor to neighbor, pastor to pastor, South Carolinian to South Carolinian," Cruz told about 800 supporters and others at a theater in downtown Charleston, emphasizing the importance of the ground game.