The wind turbines that rise out of the cornfields here reminded me on a recent drive of one postelection truth, even in the red state of Iowa. As President-elect Donald J. Trump considers whether to break the United States commitment to the Paris climate accord, the rise of clean energy across the heartland is already too well entrenched to be reversed. By 2020, thanks to MidAmerican Energy’s planned $3.6 billion addition to its enormous wind…