President Trump has already begun blasting Sen. Kamala Harris (D-Calif.), but some Republicans fear the attacks could easily deepen his own problems.

The president’s support with women has eroded over the course of his presidency, and GOP strategists are especially worried about female voters in the suburbs, who turned sharply against the party in the 2018 midterms.

Aggressive Trump attacks against Harris, whom presumptive Democratic nominee Joe Biden named as his vice presidential running mate on Tuesday, could repel the very voters Trump needs to win over.

In a Fox Business interview that aired Thursday morning, Trump referred to Harris as “sort of a madwoman,” an allegation he based upon what he called her “angry” questioning of Supreme Court Justice Brett Kavanaugh during his 2018 confirmation hearings.

Trump has also called Harris “nasty” and tweeted that she abandoned the Democratic presidential primary “with almost zero support.” He has expressed surprise that Biden chose Harris given that she had “said such bad things” to say about the former vice president during primary debates.

Harris would be only the third woman to be the vice presidential nominee of a major party, and the first nonwhite woman in that role. While anyone on the front lines of a presidential campaign expects to come under attack, descriptions of a female candidate as “nasty,” “angry” or imbalanced are widely seen as sexist tropes.

“Trump and the Trump campaign need to be very sensitive to the fact that attacks they might make against Biden could be perceived as sexist if they are made against Sen. Harris,” said Alex Conant, a GOP strategist who worked on Sen. Marco Rubio’s (R-Fla.) 2016 presidential campaign. “Given how important women voters are in this election, they can’t afford to be put on defense about whether or not an attack is sexist.”

Conant noted that this is not something that only Trump, or only Republicans, have had to deal with. He cited his own work for Sen. Joni Ernst (R-Iowa) when she first ran for Senate in 2014. Ernst was running against Democrat Bruce Braley, each seeking to replace retiring Sen. Tom Harkin (D). During the campaign, Harkin at one point said Ernst would be “wrong for Iowa” even if she were “as good looking as Taylor Swift.” Harkin later expressed regret for the remark.

Back in 2008, some Democrats were worried that Biden himself could appear patronizing to Alaska Gov. Sarah Palin, the GOP vice presidential nominee that year, during their sole debate. In the end, Biden was perceived to walk that line effectively.

There is no real question that Trump is in trouble with female voters. A Monmouth University poll this week indicated that women were breaking against Trump by almost 30 percentage points. The poll found that, among registered voters, 61 percent of women backed Biden and just 32 percent supported Trump.

In 2016, Trump lost female voters to Democratic rival Hillary Clinton — the first female presidential nominee of a major party — by 13 points, according to exit polls. But he won white women by 9 points, 52 percent to 43 percent.

Liz Mair, a GOP strategist and former online communications director of the Republican National Committee, said she believed women were reacting against Trump more out of a general resistance to his personality than anything else.

“I don’t think it is any particular scandal or comment or policy,” Mair said, comparing Trump to the kind of “narcissistic” man whose advances many women have had to fend off at some point in their lives.

“This is somebody whose ethos is reminiscent of people who women have not wanted proactively in our lives,” she said. “He is reminiscent of the guy who you go, ‘What a pest, what a nuisance, go away.’”

The Trump campaign has been trying other tactics that are widely seen as thinly veiled attempts to get moderate female voters to move back toward the president. In particular, Trump’s repeated insistence that suburban life would be endangered by a Biden presidency is seen as part of this effort.

But a Wednesday tweet in which the president raised the specter of “low income housing [that] would invade their neighborhood” — and the fact that the president suggested that Sen. Cory Booker (D-N.J.), who is Black, would be put “in charge” of this effort by Biden — raised yet another furor over implicit racism.

“We know that Trump is already trying to scare white women suburban voters with his rhetoric about protecting the suburbs,” said Karen Finney, a Democratic strategist who was a senior spokesperson for Clinton in 2016. “People just don’t seem to be buying it. I think after four years, people see through the rhetoric."

Finney knows better than most, from her Clinton experience, the perils of putting too much faith in polls or taking any votes for granted. But she argued that the kind of attacks Trump has made on Harris just reinforce traits that many female voters find off-putting.

“For voters who are already moving away from him, it reminds them of what they don’t like about Trump — the division, the meanness,” she said.

It is always possible that Trump could pull a surprise again and do better than expected or find traction with some new line of attack.

Mair cautioned against taking too glib a view of the electorate. She said that, as someone who had served as a consultant to female candidates, “I am not a big subscriber to this idea that women vote for women, and it’s all girl power and all this kind of nonsense.”

But that doesn’t change the fact that Trump's standing with women has deteriorated — and the attacks on Harris seem unlikely to change that tide.

Conant, the Republican strategist, gave a stark assessment of the stakes.

“If Trump loses, it is going to be because he underperforms with women. You look at the gender divide in this race and it is clear why Trump is trailing in all the polls. He can’t afford to give up any more ground.”

The Memo is a reported column by Niall Stanage, primarily focused on Donald Trump’s presidency.