The fall U.S. presidential campaign, beginning on Labor Day, Sept. 5, at the very end of summer, is still five months away. Yet already we can grasp its disturbing outlines. The United States is headed for an unusually bitter, divisive general election campaign this year, focused on the Midwestern Rust Belt. And there is a nontrivial, although still outside, prospect that Donald Trump, an American Berlusconi, could be elected as America's next leader.

Hillary Clinton is now almost certainly the Democratic nominee, with a 4-3 lead with close to half of the elected delegates already chosen. Additionally, she has virtually all the party's superdelegates — party officials, governors, congressmen and so on — who are not chosen through the electoral process. Yet Sanders has amassed over 6 million votes, nearly 80 percent of Clinton's total, and won several important states, including Michigan, Washington, Hawaii and Alaska.

Numerous warning signs suggest that Clinton could be vulnerable in the general election. Fifty-three percent of the public has an unfavorable opinion of her, despite her many accomplishments, according to Gallup. She has the email scandal, which the FBI is still investigating. One-third of Sanders voters say they would not vote for Clinton in November. Clinton has strong majorities among minority voters, to be sure, including blacks and Latinos, but has not done well with white voters, including students. Clinton has lost Michigan, upper New England, several Midwest states, and the Pacific Northwest to Sanders, an elderly democratic-socialist senator, in a country with no socialist tradition.