The Framers of the Constitution envisioned Congress as the keystone of our political architecture, but Americans today do not see it that way. For the last 100 years or so, people have tended to pay almost exclusive attention to the executive. In presidential election years, this means people have little interest in the race to control the branch of government the Founding Fathers tied most closely the people.
The Trump candidacy has exacerbated this bad civic habit. These days, we cannot have a conversation about anything other than Trump (which seems to be just the way the Republican nominee likes it), so there is even less talk of the House and Senate than usual. Still, there is a congressional election just weeks away, whether people have noticed it or not.
The Republicans control both chambers of Congress at the moment. What are the chances they retain their majorities? Inevitably, that question entangles us with Trump, who creates unique problems for electoral prognosticators.