Democrats who favor a more aggressive approach say that Republicans are rewriting the rule book. McConnell’s refusal to hold a vote, or even a hearing, for Obama Supreme Court nominee Merrick Garland continues to anger those who say that by rights it should be liberals, not conservatives, who are cementing their Supreme Court majority.

Trump, too, has upended many norms, including by largely rejecting congressional oversight and refusing to release his tax returns. In some states, Republican-led legislatures have reacted to a Democrat’s winning the governor’s office by reducing the power of the office.

The question facing Democrats is whether the right response to all this is to fight back with similar aggression or try to restore a greater sense of unity to the country. Some candidates think that voters have grown fatigued with the animosity and liken the political parties to children bickering in the back seat of a car.