Mr. Biden will win the popular vote, and he may eke out a narrow win in the Electoral College. In essence he’ll have reversed Mr. Trump’s victory in 2016 with hair’s-breadth advantages in Wisconsin and Michigan, and perhaps Pennsylvania, Georgia and Arizona. None of them will be by large margins. He will have vanquished an incumbent president, which is no easy task.

But look down the ballot, or across the country, and Mr. Biden’s potential victory looks remarkably limited and personal. Most new presidents enter office having swept allies into Congress and statehouses as the public embraces his agenda and vision for America. Certainly this was true of Barack Obama in 2008 and to a lesser extent Mr. Trump in 2016. Mr. Biden had no such coattails.

Democrats lost seats in the House, giving up some of the suburban gains they made in 2018 while continuing to struggle in rural areas. The full results won’t be in for weeks, but Speaker Nancy Pelosi may find her majority cut in half or more to the smallest in 20 years.