ERIE, PA. -- Republican presidential nominee Donald Trump escalated his personal attacks on his Democratic rival, Kamala Harris, on Sunday by repeating an insult that she was ā€œmentally impairedā€ while also saying she should be ā€œimpeached and prosecuted."

Trump's rally Sunday in Erie, Pa. , took on similar themes as an event one day earlier that he described himself as a ā€œdark speech.ā€ He told a cheering crowd that Harris was responsible for an ā€œinvasionā€ at the U.S.-Mexico border and "she should be impeached and prosecuted for her actions.ā€

ā€œCrooked Joe Biden became mentally impaired,ā€ he added. ā€œSad. But lying Kamala Harris, honestly, I believe she was born that way. Thereā€™s something wrong with Kamala. And I just donā€™t know what it is but there is definitely something missing. And you know what, everybody knows it.ā€

With just over a month until the election, Trump is intensifying his use of personal and offensive attacks, even as some Republicans say he'd be better sticking to the issues.

His suggestions that political enemies be prosecuted are particularly notable for their departure from norms in the U.S. in which the judicial system is supposed to be protected from political influence. In recent weeks, he has threatened prosecutions of Google for allegedly giving priority to ā€œgood storiesā€ about Harris, Meta CEO Mark Zuckerberg, and anyone he deems to be ā€œinvolved in unscrupulous behaviorā€ related to the coming election.

His derision of the first Black woman and person of South Asian descent to lead a major party ticket as ā€œstupid,ā€ ā€œweak,ā€ ā€œdumb as a rockā€ and ā€œlazyā€ is also a sign of how nasty and personal the final stretch of the campaign may be.

Donald Trump

His allies have pushed him publicly and privately to talk instead about the economy, immigration and other issues.

ā€œI just think the better course to take is to prosecute the case that her policies are destroying the country,ā€ said Sen. Lindsey Graham, R-S.C., on CNN's ā€œState of the Union" Sunday when asked about Trump's comments. ā€œTheyā€™re crazy liberal.ā€

When asked whether he approved of the personal attacks on Harris, Rep. Tom Emmer, R-Minn., sidestepped during an interview on ABCā€™s ā€œThis Week.ā€

ā€œI think Kamala Harris is the wrong choice for America,ā€ said Emmer, who is helping Trumpā€™s running mate JD Vance prepare for Tuesdayā€™s vice-presidential debate. ā€œI think Kamala Harris is actually as bad or worse as the administration that weā€™ve witnessed for the last four years.ā€

When pressed, Emmer said: ā€œI think we should stick to the issues. The issues are, Donald Trump fixed it once. They broke it. Heā€™s going to fix it again. Those are the issues.ā€

Former Maryland Gov. Larry Hogan, running for the Senate as a moderate Republican, brought up Trump's false claims that Harris, the daughter of Jamaican and Indian immigrants, had previously played down her Black heritage. Harris attended Howard University, a historically Black college, and has identified as both Black and South Asian consistently throughout her political career.

ā€œIā€™ve already called him out when he had the one interview where he was questioning her racial identity, and now heā€™s questioning her mental competence," Hogan told CBS' ā€œFace the Nation.ā€ ā€œAnd I think thatā€™s insulting not only to the vice-president but to people who actually do have mental disabilities.ā€

Harris has not commented on Trumpā€™s recent attacks but has said when asked about other comments that it was the ā€œ same old show. The same tired playbook weā€™ve heard for years with no plan on on how he would address the needs of the American people.ā€

Ahead of the rally on Sunday, some of Trump's supporters said he often makes offensive remarks. Still, they support his proposals to restrict immigration and said he would have a better handle on the economy.

Donald Trump

ā€œHe says whatā€™s on his mind, and again, sometimes how he says it isnā€™t appropriate,ā€ said Jeffrey Balogh, 56, who attended the rally with two friends. ā€œBut he did the job. He did very well at it.ā€

Tamara Molnar said she thinks Trump is very strong on immigration. As for his insults, Molnar said: ā€œI think everybody has to have some decorum when speaking about other candidates, and I donā€™t think either side is necessarily innocent on that. Thereā€™s a lot of slinging both ways.ā€

At the rally in Erie, Trump said the ā€œinvasionā€ would end and deportations begin if he took office.

ā€œThousands of migrants from the most dangerous countries are destroying the character of small towns and leaving local communities in anguish and in despair,ā€ he said, talking about communities in the battleground states of Wisconsin, Michigan and Pennsylvania.

Last month, the GOP leader said he was ā€œentitledā€ to personal attacks against Harris.

ā€œAs far as the personal attacks, Iā€™m very angry at her because of what sheā€™s done to the country," he told a news conference then. ā€œIā€™m very angry at her that she would weaponize the justice system against me and other people, very angry at her. I think Iā€™m entitled to personal attacks.ā€