The vice president will be central to President Biden’s re-election efforts, particularly on the issue of abortion access. Both critics and supporters say the increased spotlight is a good thing.WASHINGTON — Kamala Harris, the vice president, was featured heavily throughout a video that President Biden used to announce his 2024 campaign on Tuesday, a strong signal that she will be a central part of his re-election efforts.Somehow, both her harshest critics and her staunchest allies see this as a good thing.To her supporters, Ms. Harris, 58, represents broad swaths of the American electorate that Mr. Biden does not: She is a woman, she is biracial and she is decades younger than the 80-year-old president, who would be 86 at the end of a second term. She is seen as the administration’s most visible advocate on issues including voting rights, access to abortion and combating climate change.But her detractors — who include both Republicans and Democrats — say she is unprepared for the scrutiny that is sure to come her way as she positions herself as the potential heir apparent to a Biden presidency. And some do not think the issues in her portfolio will appeal to the independent and moderate voters who tend to decide presidential elections.“What swing voter wakes up and says, ‘Boy, Kamala Harris is going to move me?’” said Mike Murphy, a political strategist who was a longtime adviser to John McCain, the Republican senator and presidential candidate. Mr. Biden and Ms. Harris are still betting that the case they are making to America — that their administration represents the protection of civil liberties and the return of stable governing — will have broad appeal. Hours after Mr. Biden announced his re-election bid on Tuesday, Ms. Harris participated in events that were designed to present her as an emissary of the president but also showcase the ways in which their roles will differ on the campaign trail.On Tuesday afternoon, she appeared alongside President Yoon Suk Yeol of South Korea, who is in Washington this week for a state visit, at the National Aeronautics and Space Administration Goddard Space Flight Center. There, the two promoted joint projects between the South Korean and U.S. governments and said they would work together to monitor the threat of climate change.Later in the evening, the vice president previewed a fiery and polished campaign style as she attended an event promoting abortion rights, an issue that is likely to define the 2024 race and one that Republicans are struggling to build a unified platform around.She spent her first night on the trail visiting Howard University, a historically Black college and her alma mater, to participate in a rally co-hosted by Planned Parenthood and NARAL Pro-Choice America. Howard students chanted “Four More Years” and gave Ms. Harris a standing ovation as she took the stage.“We are living, I do believe, in a moment in time where so many of our hard-won freedoms are under attack,” Ms. Harris said. “And this is a moment for us to stand and fight.”She criticized the Supreme Court for taking a constitutional right “from the women of America” and assailed “extremist” Republicans around the country for passing restrictive abortion laws, including those that outlaw the procedure in cases of rape and incest — “clearly, most of them don’t even know how a woman’s body works,” she remarked at one point.“Immoral, outrageous, that people who dare to walk around expecting you to respect them, and elect them, would do these kinds of things to other human beings and strip them of their right and entitlement to dignity and autonomy,” Ms. Harris said.An increased number of appearances by Ms. Harris will mean that conservative media outlets like Fox News will have more opportunities to scrutinize everything from the substance of her remarks to her body language, a practice that the vice president’s allies say is rooted in sexism and racism.Some conservative critics have tried to make the case that a vote for Mr. Biden is really a vote for President Harris. On Tuesday, a campaign ad released by the Republican National Committee juxtaposed an image of the president and vice president against artificially generated doomsday scenes.“Republicans will definitely try to make the race as much about her as possible because they see her as more vulnerable, more unpopular,” Tim Miller, a political strategist and communications director for Jeb Bush’s 2016 presidential campaign, said in an interview. But like Mr. Biden, Ms. Harris has low approval ratings: A recent poll found that 36 percent of Americans think she is doing a good job.“I think she’ll play a more significant role than another V.P. would in another situation,” Mr. Miller added.Vice President Kamala Harris hugging Justin J. Pearson at Fisk Memorial Chapel in Nashville, Tenn., earlier this month, after he was ousted as a state representative in a move that some saw as racially motivated. He was later reinstated. Jon Cherry for The New York TimesMs. Harris came into the Biden administration with an undefined portfolio and stepped into one of the trickiest roles in American politics. She has spent the past two years trying to establish her legacy amid frequent staff turnover and thorny assignments, including addressing the root cause of migration from Central America to the United States. During the first months of his presidency, Mr. Biden referred to her as a “work in progress,” according to Chris Whipple, who wrote a book on the Biden presidency.Several current and former aides said she began to find her footing when she requested to be the administration’s leader on voting rights — only to remain the public face of the issue as legislative efforts to expand ballot access died in Congress.In recent months, she has established herself as an advocate of police reform and as the standard-bearer for the administration on abortion rights since Roe v. Wade, which established a constitutional right to abortion, was overturned by the Supreme Court last summer.In recent weeks, Ms. Harris has also traveled to help further Mr. Biden’s calls for stricter gun control measures amid a series of mass shootings. In early April, she made a last-minute trip to Nashville to meet with State Representatives Justin J. Pearson and Justin Jones, two Democratic lawmakers who were expelled for protesting for gun control on the Tennessee House floor and later reinstated. She also met with the two lawmakers, who are Black, alongside the president in Washington this week.“There’s an agenda at play,” Ms. Harris said at Howard. “They even went so far that they had to turn off the microphones on two young elected leaders in Nashville because they couldn’t even stand it. They couldn’t even handle it, these people who want to call themselves leaders.”Ms. Harris’s supporters say they see enormous potential for the vice president to bolster her reputation and further define her legacy as the campaign season approaches. Lt. Gov. Eleni Kounalakis of California, who visited Ms. Harris last week in Washington, said the vice president had grown into her role. She added that Ms. Harris would be able to showcase more of her skills on the campaign trail this time than in 2020, during the height of the pandemic.“Particularly with the younger climate activist leaders in the room, and particularly with people of color, she is an inspirational champion,” Ms. Kounalakis said. “Connecting with real people on the campaign trail is very natural for her, and where she truly thrives.” More