These races will give early clues about who will win the House

Control of the House is up for grabs, and political observers of all stripes will be watching on Tuesday with anxious anticipation for early signs of which party will hold the gavel in the next Congress. Election forecasters have singled out dozens of highly contested seats — some of them “toss-ups” and some “leaning” in favor of one party or the other — that will determine whether Republicans keep the majority or Democrats return to power after two years in the minority wilderness. But not all battleground seats are created...