Wisconsin’s highly engaged voters routinely post some of the highest turnout numbers in presidential elections. On Tuesday, they will play an important role in both major-party nominating contests. Check out some of the things we will be watching.

Look to the north

Donald J. Trump hit a rough patch, to put it mildly, in the run-up to Wisconsin, where he trails Senator Ted Cruz of Texas in statewide polls. A victory for Mr. Cruz, who has mostly won in caucus states up till now, would demonstrate that his appeal is growing, and would be an indicator of lasting damage to Mr. Trump’s candidacy.

“Trump needs to regain some momentum after a disastrous week,” said Brian Walsh, a Republican strategist unaffiliated with the candidates. “Cruz needs to demonstrate that he can win a big-state primary besides Texas.”

But even if Mr. Trump lost the statewide vote count, and the 18 delegates that go with it, he could still mitigate the damage by winning in Wisconsin’s Seventh and Eighth Congressional Districts, predominantly rural and heavily blue-collar districts covering much of the state’s northern half.