It was impossible not to feel a sense of relief watching the Democratic debate after months dominated by the Republican circus of haters, ranters and that very special group of king killers in Congress. For those despairing about the future of American politics, here was proof that it doesn’t have to revolve around candidates who pride themselves on knowing nothing or believe that governing is all about destroying government.

Civility was a big winner on Tuesday night, and the discussion of real issues was refreshing. But what stood out most was the Democratic Party’s big tent, capable of containing a spectrum of reality-based views. All five candidates — including two refugees from what had been the Republican Party, Lincoln Chafee, a former Republican senator, and Jim Webb, secretary of the Navy in the Reagan administration — have real records. They also have real differences on important issues — national security, foreign policy, gun safety, financial reforms. Those differences illuminate the choices that have to be made in governing, some likely to be successful, some ineffective.

The debate probably won’t change much in the polling. Hillary Rodham Clinton reminded us why she’s the front-runner, with her experience, command of the issues and strength in communicating ideas. She seemed both at ease and fearless. It helped that the candidates actually valued time to discuss issues. One of the biggest applause lines was Senator Bernie Sanders’s quip to Mrs. Clinton, “the American people are sick and tired of hearing about your damn emails.” Supporters of Mr. Sanders embraced his passionate critiques, but his performance may not convert those skeptical of his ability to broaden his appeal.

The biggest point of agreement was on income inequality, the central theme of the Sanders campaign and one that has been put on the top of the agenda by the other candidates as well. The question, of course, is how to reduce it in an economic system that has been moving toward ever greater inequality. Mr. Sanders said he would change the tax code to have the wealthiest pay a lot more, with new revenues going to education, free college tuition and health care for all. Mrs. Clinton would also raise taxes, and said she supported reining in “the excesses of capitalism so that it doesn’t run amok,” though it’s not clear what that would take, given the trajectory we’re on.