Washington — Donald Trump and Kamala Harris are locked in a tight race in three key battleground states heading into their first debate on Tuesday, but Harris leads in a couple of areas. One is the “excitement factor”: Democrats in Pennsylvania, Michigan and Wisconsin are more excited about what they’ve seen from Harris’ campaign recently than Republicans are about what they’ve seen from Trump’s, according to a new CBS News poll.

Eighty-nine percent of Democrats in Michigan, 82% in Pennsylvania and 87% in Wisconsin say they’re excited by Harris campaign. By comparison, among Republicans, 78% said the same of Trump in Michigan, 75% in Pennsylvania and 76% in Wisconsin. 

The changes at the top of the Democratic ticket that followed President Biden’s departure from the campaign in July upended the race just months to go before Election Day, as Democrats are trying to continue to capitalize on any momentum and sustain excitement heading toward November. 

Now, Democrats in the three battleground states are also just as likely as Republicans to say they will definitely vote, as Harris has consolidated the votes among the party’s base. But Trump leads in the states among some key issues, including the economy and inflation.

In a national survey conducted before Harris formally accepted the nomination last month, most Democrats were excited about the vice president, and more Democrats said they would vote since she became the nominee. Her campaign also announced huge fundraising numbers, $540 million for August, nearly triple what Trump raised. But whether Harris can sustain the excitement and channel it into a lead in the battleground states remains to be seen. 

One measure that’s very different since Mr. Biden and Trump faced off in June is that now it’s Harris who’s seen by more as having the cognitive and mental health to serve, and Trump comparatively less so. In Michigan, 64% say she has the cognitive and mental health to serve, compared with 47% for Trump. In Pennsylvania, it’s Harris with 64% again on this question and 49% for Trump. And in Wisconsin, Harris has her widest margin on Trump on this question, 68% to 48%. This was very different in CBS News’ national polling conducted when Mr. Biden was still running: 35% of registered voters thought he had the cognitive and mental health to serve, and 50% thought Trump did. 

Earlier this month, the Harris campaign worked to tamp down expectations, saying that while “Americans are energized behind that message,” citing fundraising success, volunteer interests and a “spike in enthusiasm,” the fight ahead is a serious one. 

“Make no mistake,” Campaign chair Jen O’Malley Dillon said in a memo. “We head into the final stretch of this race as the clear underdogs.”

contributed to this report.