Vice President Kamala Harris will travel to Arizona on Friday to assail former President Donald J. Trump over abortion restrictions, with plans to blame him for bans in the state and across the country.

In her remarks at a rally in Tucson, Ms. Harris will lean into the Biden campaign’s new attack line on laws pushed by Republicans that have cut off abortion access for millions of American women: Donald Trump did this.

This week, Arizona became the center of the national debate on reproductive rights after a ruling by the state’s top court upheld an 1864 law banning nearly all abortions. The decision gave Democrats around the country an opportunity to focus their races on abortion rights, a strategy that has led to unexpected victories for the party over the last two years. The Biden campaign has already released two new ads this week hammering Mr. Trump on abortion.

“The overturning of Roe was a seismic event,” Ms. Harris is expected to say in Tucson, according to a copy of her prepared remarks distributed by the Biden campaign. “And this ban in Arizona is one of the biggest aftershocks yet.”

Ms. Harris’s comments on Friday may be some of the most direct and extended attacks that she has made against Mr. Trump on the issue. While she has appeared frequently at events about abortion rights, she has often done so in her official capacity, limiting her ability to criticize Republicans. The event in Tucson, however, is a campaign rally, meaning Ms. Harris can speak more freely.

“We all must understand who is to blame,” her prepared remarks say. “It is the former president, Donald Trump. It is Donald Trump who, during his campaign in 2016, said women should be punished for seeking an abortion.”

The vice president’s trip to Arizona was planned before the ruling and was originally supposed to involve an official event on student debt. But even before the court ruling, Ms. Harris insisted that abortion rights become the focus instead and that the campaign take over, according to three Democratic officials familiar with the planning.

The timing could not have been better for the Biden campaign. On Monday, Mr. Trump released a video saying that abortion restrictions should be left up to the states. The next day, the Arizona Supreme Court upheld a prestatehood law banning nearly all abortions, without exceptions for rape and incest. (The law, which Mr. Trump has since criticized, has not yet gone into effect.)

Republicans have been left on the defensive, including Kari Lake, the Trump ally running for an open Senate seat in Arizona. Two years ago, when she was running for governor, Ms. Lake called the Civil War-era abortion ban “a great law.” But on Thursday, she released a five-minute video, saying that “this total ban on abortion” was “out of line with where the people of this state are.”

“I chose life,” said Ms. Lake, who has two children, of her own pregnancies. “But I’m not every woman. I want to make sure that every woman who finds herself pregnant has more choices so that she can make that choice that I made.”

Ms. Lake’s stark shift shows how much the politics of abortion have changed since Supreme Court justices appointed by Mr. Trump ruled in favor of a Mississippi law in Dobbs v. Jackson Women’s Health Organization and abolished the constitutional right to abortion.

“This is the first presidential election since Dobbs. And it is a massively important issue because it does affect every woman in some capacity. It just does,” said Stephanie Schriock, former president of Emily’s List, the powerful organization that seeks to elect Democratic women who support abortion rights. “It crosses people’s minds because women are dealing with this stuff all the time, particularly those of reproductive age, which is a pretty big swath of all of Gen Z and millennials.”