10 Elections To Watch In Nevada, South Carolina And Texas

This week’s primaries are a gamble — and not just because many of them are in Nevada. Former President Donald Trump is backing challengers to not one but two incumbent members of Congress, which will once again put the power of his endorsement to the test. Meanwhile, both parties face decisions about how far right or left of center a nominee can be in a swing seat and still stand a chance of winning in November.

All told, four states are holding primaries on Tuesday: Maine, Nevada, North Dakota and...