washington u.s. republican presidential candidate marco rubio campaign urge tactical vote party front-runner donald trump friday say rubio supporters ohio vote state governor john kasich next week ohio one five state hold republican primary contest march 15 republican primary voter ohio want donald trump nominee john kasich best bet rubio spokesman alex conant tell cnn interview republican primary voter florida want donald trump nominee marco rubio best bet indisputable add refer u.s. senator home state rubio kasich ted cruz u.s. senator texas battle stop trump win nomination represent party nov. presidential election republicans notably 2012 republican nominee mitt romney urge conservatives oppose trump vote ever alternative candidate likely win certain state upcoming primary contest report susan heavey tim ahmann edit frances kerry article fund part sap independently create reuters editorial staff sap editorial involvement creation production rubio campaign urge supporters ohio back kasich