sunday roundup week nation enter terra incognita indiana gop voter hand donald trump big victory give ted cruz john kasich drop unqualified  USA able dangerous nominee  USA  history event immediately provide test republicans rise occasion refuse endorse trump rick perry call trump cancer say consider running mate open way help go stir statesmanship test gop test medium david roberts write likely unusual campaign usual medium treatment trump obvious unfitness office today widely acknowledge party mainstream medium partisan observation yes medium write republicans handle character test need remember face important mistake medium treat like normal election donald trump like normal candidate