Originally Published: 06 AUG 23 06:02 ET

By Daniel Strauss, CNN

(CNN) — Republican presidential candidates are increasingly making Vice President Kamala Harris their prime target as they jockey for attention from voters, focusing on the No. 2 Democrat rather than President Joe Biden.

In statements, speeches, televised interviews and emails, they suggest that a vote for Biden, who would be 82 at the start of his next term, would really be a vote for an even more unpredictable and dangerous presidency under Harris, 22 years his junior.

Florida Gov. Ron DeSantis was all too eager to get into an extended back-and-forth with Harris in recent days when the Florida governor defended the state’s new Black history curriculum after Harris panned the history standards as “extremists” just “pushing propaganda on our children.” That spurred a multi-day back-and-forth between DeSantis and Harris that reached a point where DeSantis’s office published a letter inviting the vice president to debate him in Florida (Harris declined).

It was the latest example of DeSantis’ – and other candidates’ – eagerness to throw down with the vice president. They want to contrast themselves not just with each other or Biden, but Harris, too.

The differences can be seen in Harris’ own campaigning, which has involved focusing on issues where Republicans and Democrats share virtually no middle ground. On the same day that nearly the entire GOP field attended the Lincoln Day Dinner in Des Moines, she traveled to the same city to discuss abortion rights.

It’s not unheard of for a presidential campaign to take aim at an opposing campaign’s vice presidential pick. In 2004, the George W. Bush reelection campaign went out of its way to portray then-Sen. John Edwards as a policy lightweight. And in the 2008 presidential race, then-Sen. John McCain liked to mock Biden as “Joe the Biden” in stump speeches. Democrats at the time warned that if McCain won, then-Alaska Gov. Sarah Palin would be one heartbeat away from the presidency – akin to the argument being made by Republicans about Harris and Biden now.

“Anyone is better than President Kamala Harris. Anyone,” former South Carolina Gov. Nikki Haley said during an appearance on Fox News in July.

She was asked whether she meant Biden. She didn’t.

“Well, I think it’s President Harris… A vote for President Biden is a vote for Kamala Harris,” she said.

Similarly, during a June stop in Georgia, DeSantis offered the specter of a Harris presidency as something worse than a second Biden term.

“We’re running to win and to deliver, and that’s really the only reason to run, and I feel compelled to do it, because I think that if we, if we muff this one and Biden gets in again – heck you may end up with Kamala as president.”

In an April town hall in New Hampshire, former New Jersey Gov. Chris Christie went even further, linking voting for Trump to Harris becoming president.

“And let me promise you that he is the nominee in 2024, Joe Biden will be the president in 2025 at 83 years old. If you think his act looks bad now, wait until he’s 83 and 84 and 85 and 86. And by the way, in case he doesn’t. You get Kamala Harris. A vote for Donald Trump is a vote for Kamala Harris,” Christie said. “Because by the tables, it’s more likely than not that Joe Biden won’t make it. So if you’re okay with Kamala Harris, that’s fine. That’s your call. It’s your choice.”

The prospect of Harris becoming president is really the core reason Republicans are making these attacks, said Mike DuHaime, a top Republican strategist advising Christie’s presidential campaign.

“Most VPs are not popular with the other party. Dick Cheney wasn’t popular with Democrats. Al Gore wasn’t popular with Republicans. So it’s not like anything new that she’s unpopular with the opposing party,” DuHaime said. “What’s new is that people think there’s a more legitimate chance of her actually ascending to the presidency than previous VPs and anyone that I can remember.”

The attacks are also coming as the both the president and vice president deal with low approval numbers. A SSRS/CNN poll from July found Harris’s approval numbers underwater with 57% disapproving of her while 42% approving of her. The same poll found Biden’s own approval numbers in almost the exact same place –55% disapproved and 44% disapproved.

“There’s very little political cost to attacking her – especially as she tries to raise her profile,” Republican strategist Alex Conant said.

Democrats write these attacks off as something meant to just stoke up the Republican primary electorate.

“It’s a GOP base aversion play more than anything else,” Democratic pollster Cornell Belcher said. “It’s politics 101: she, because of who she is and what she represents, she is a great strawman(woman)/ boogieman to play off of and that’s what you want when campaigning. Being against the most prominent national current symbol of diversity and feminist power is a no brainer.”

The White House and the Biden campaign did not comment.

Harris herself has shifted her strategy, as demonstrated by her back-and-forth with DeSantis this week. As CNN reported previously, the White House and the campaign are looking to capitalize on confronting what they view as Republican extremist attacks on personal freedoms and rights.

“We will not stop calling out and fighting back against extremist so-called leaders who tried to prevent our children from learning our true and full history,” she said during an event in Florida this week.

Harris’ Republican critics like to say she bungled one of the biggest assignments in her policy portfolio: immigration and the US-Mexico border, an important topic for Republican voters. They also note that she’s prone to unforced errors, like when she went to West Virginia to promote the Biden administration’s Covid-19 stimulus proposals but didn’t let West Virginia Sen. Joe Manchin know ahead of time, or when she misspoke and said the United States had to “reduce population” to combat climate change.

“GOP candidates who have a strong, effective message will use Harris as a news hook to attack Biden because she’s made headlines saying crazy things like ‘the border is secure,’” Gail Gitcho, a Republican strategist who served as then-Gov. Mitt Romney’s 2012 presidential communications director, said in an email. “…Using the #2 on the ticket as a way to chip away at the top of the ticket. Republicans view her as someone who can mangle a message and create viral statements – not unlike what Dan Quayle and Sarah Palin were to Democrats.”

Still, there’s one key Republican who hasn’t spent much time criticizing Harris. Former President Donald Trump, the primary’s frontrunner, has focused more on DeSantis and Biden on the campaign trail.

But that’s been during primary season.

If Trump gets the GOP nomination again, he’s likely to split some of his criticism between Biden, his Republican critics, and Harris as well.

“I think it’s going to be a contrast that whoever the nominee is is going to make,” DuHaime said.