Five states head to the polls on Tuesday in primary elections that will set up some of the most critical contests to determine control of Congress next year.

Five states head to the polls on Tuesday in primary elections that will set up some of the most critical contests to determine control of Congress next year.

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Primaries in Maine, Nevada, North Dakota, South Carolina and Virginia: What to watch

Five states head to the polls on Tuesday in primary elections that will set up some of the most critical contests to determine control of Congress next year.