Whatever doubts existed about the Republican grip on the House should now be gone.

By picking up at least a dozen House seats in the elections last Tuesday, the Republicans cemented a nearly unassailable majority that could last for a generation, or as long as today’s political divides between North and South, urban and rural, young and old, and white and nonwhite endure.

Democrats might well reclaim the Senate and hold the presidency in 2016. But any Democratic hopes of enacting progressive policies on issues like climate change and inequality will face the reality of a House dominated by conservative Republicans. The odds that the Republicans will hold the Senate and seize the presidency are better than the odds that Democrats will win the House, giving the Republicans a better chance than Democrats of enacting their agenda.