Harris Faces Challenge of Translating Convention Joy to Fall Momentum

Joy cometh in the morning, but so do hangovers. The party in Chicago is done, the confetti has been swept up, the pictures have been posted to social media. But the real question as exuberant Democrats woke up on Friday was whether they could channel the sheer intoxication of the United Center into a sustained, 74-day sprint to Election Day.

Vice President Kamala Harris emerged from her nominating convention with a burst of momentum that Democrats hardly expected barely a month ago, when they thought they would be tethered to a possibly doomed re-election bid by President Biden. She has rejuvenated a once demoralized party and given a jolt of optimism to Democrats who now see victory in reach.

The buzzkill reality, however, is that victory is anything but assured. The thousands of jubilant delegates in the hall this week were not representative of the swing voters that Ms. Harris needs to defeat former President Donald J. Trump. History is littered with presidential candidates who roused their partisans at conventions only to fall short come November. And whatever else he is, Mr. Trump is no pushover. Ms. Harris can expect a bruising battle over the next two and a half months.

She knows that, of course, and veterans of past campaigns, including former President Bill Clinton and the former first lady Michelle Obama, made a point of warning ecstatic Democrats this week to temper their heady expectations. Ms. Harris has had one of the most impressive debuts of any general election candidate in recent times, yet she still faces polls within the margin of error.

“The energy here is electric,” Representative Hillary Scholten, Democrat of Michigan, said minutes before Ms. Harris’s acceptance speech on Thursday night. “But I