A key Obama-era strategist says Kamala Harris may be riding the hype wave, but it's still Trump's race to lose

• Swapping Joe Biden for Kamala Harris doesn't mean the Democratic Party is guaranteed a win this November.
• The former Obama advisor David Axelrod said that "it's absolutely Trump's race to lose right now."
• "Everybody should be sober about that on the Democratic side," Axelrod told CNN.

Vice President Kamala Harris is still in for a tough fight if she wants to beat former President Donald Trump this November, the former Obama advisor David Axelrod says.

Axelrod told CNN's Jessica Dean in an interview on Saturday that Democratic supporters might be getting ahead of themselves if they thought Harris was a shoo-in this November.

"There's a lot of irrational exuberance on the Democratic side of the aisle right now because there was despair for some period of time about what November was going to look like," Axelrod said.

Harris' ascension as presumptive Democratic nominee on Tuesday capped off weeks of uncertainty in the Democratic Party, as party leaders began to question President Joe Biden's ability to win given his age.

The president had faced growing calls from party leaders and donors to step down after giving a disastrous performance in a debate with Trump in late June. Biden eventually dropped out of the race on July 21 and endorsed Harris as his successor.

But replacing Biden with Harris doesn't mean Trump's defeat is now certain, says Axelrod, who served as the key strategist behind President Barack Obama's victories in the 2008 and 2012 elections.

"Now people feel like there's a chance. But it's absolutely Trump's race to lose right now. He is ahead, and he is ahead in most battleground states," Axelrod said.

"I think it's a wide-open race, but Trump has the advantage right now, and everybody should be sober about that on the Democratic side," he added.

For their part, the Trump campaign had long been preparing to battle a Biden-led Democratic ticket .

"I don't think Joe Biden has a ton of advantages. But I do think Democrats do," Trump's campaign advisor Susie Wiles told The Atlantic's Tim Alberta in March.

In fact, Biden's sudden departure seems to have caught them off guard, with Trump's running mate, Sen. JD Vance of Ohio, even telling donors last month that the last-minute switch to Harris felt like a " political sucker punch ."

"The bad news is that Kamala Harris does not have the same baggage as Joe Biden, because whatever we might have to say, Kamala is a lot younger. And Kamala Harris is obviously not struggling in the same ways that Joe Biden did," Vance said, according to a recording obtained by The Washington Post .

Representatives for the Harris and Trump campaigns didn't immediately respond to requests for comment from Business Insider sent outside regular business hours.