Nikki Haley will travel to Michigan on Sunday after suffering a decisive loss in her home state of South Carolina, marking her fourth straight defeat in the Republican presidential primary. Donald Trump continued his undefeated streak with a double-digit win in South Carolina, further cementing his hold on the Republican party and raising more questions about Haley’s decision to remain in the primary.As she addressed supporters at an election night party in Charleston on Saturday, Haley deftly framed her candidacy as a moral imperative for the many voters who express dissatisfaction with…