Now that President Joe Biden is out of the race and Vice President Kamala Harris is in, former President Donald Trump is having to pivot his campaign to a new challenger.

Here are five ways the race is different with fewer than 100 days to go before Election Day.

Trump is the oldest nominee in the race

Trump had honed his attacks on the 81-year-old Biden, with his campaign and Republican allies frequently calling attention to the Democratic president's physical and verbal stumbles. While many voters were similarly concerned about Trump's readiness, polls suggested more Americans questioned Biden.

Now, the 78-year-old Trump is running against a 59-year-old candidate. And that turns the age question more on him.

The Democrats now have enthusiasm and more funding

Harris has generated massive enthusiasm and money that Biden could not generate. Her supporters are organizing Zoom calls and raising millions of dollars at a time, the latest being a White Dudes for Harris call that generated $3.7 million for her campaign.

The question is how does she turn that into votes. Can Democrats leverage all of that enthusiasm when they're organizing efforts and turning out voters?

Trump has to find new arguments

Harris comes into the campaign relatively fresh. Trump and his allies are trying to saddle her with the liabilities of the Biden administration but also run against her as a distinct candidate.

Trump on Monday launched a 30-second advertisement that targets Harris' work on migration issues, dubbing her the "border czar" and blaming her for illegal crossings into the United States. After displaying headlines about crime and drugs, the video brands Harris as "Failed. Weak. Dangerously liberal."

Harris has to pave her own path

The vice president needs to show what kind of candidate she could be. Biden was pitching ideas for a second term as president but also asking to be rewarded for his administration's accomplishments.

Harris, as his second in command, inherits some of his liabilities, particularly on inflation and the border. She will also get to take credit for the administration's accomplishments, but she has to spin it forward and set her own policy priorities.

Her first campaign for the presidency ended before she could reach the Iowa caucuses. The early promise of her 2020 presidential campaign met a more complicated reality as she spent the next 10 months struggling to break through a crowded field of candidates and churning through staff and cash.

The Electoral College math has shifted

Biden's struggles had made many Democrats fear that their electoral map was reduced to Rust Belt states that Trump won in 2016 and Biden flipped in 2020 -- Wisconsin, Michigan and Pennsylvania.

Strategists on both sides believed that Georgia and Arizona, Sun Belt states that Biden also flipped, were moving away from the Democratic president.

Now, with Harris in the race, packed Zoom gatherings and interviews with supporters are signs of rekindled enthusiasm among key Democratic voting blocs: younger voters, voters of color and Black women. That could make Democrats more confident that they're facing a competitive Electoral College map and perhaps changes the Trump team's assumptions on states it could flip.

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