Support for a wall is now routine, and some presidential candidates say they would use military force to secure the border if elected.The blistering immigration policy that Donald J. Trump enacted when he was in the White House shifted his party’s baseline on the issue to the right.His policies are now standard Republican fare: Calls to “build the wall” once set apart the right-wing fringe, but several Republican candidates now support even more exceptional measures, such as using military force to secure the border or ending birthright citizenship.Here is a look at where the candidates stand.Donald J. TrumpHis policies cemented hard-line immigration stances in the G.O.P. mainstream.Mr. Trump’s administration separated thousands of migrant families — traumatizing children and causing a public outcry. As recently as May, during a CNN event, he did not rule out reinstating that policy.His administration also forced asylum seekers to remain in Mexico while awaiting hearings, leading to the development of squalid refugee camps, and held children in crowded, unsanitary facilities.While his signature campaign promise in 2016 was to build a border wall, fewer than 500 miles of barriers were built along the nearly 2,000-mile southern border, largely in places that already had them. (At points, he suggested spikes, a moat and permission for officials to shoot migrants in the legs.)Mr. Trump toured the southern border wall near Alamo, Texas, in January 2021. Some of his 2024 rivals say they would continue work on the border wall; Mr. Trump built fewer than 500 miles during his tenure.Doug Mills/The New York TimesOne of his first actions upon taking office was to ban travelers from several majority-Muslim countries. In 2019, he began denying permanent residency to immigrants deemed likely to require public assistance, a rule that disproportionately affected people from Latin America, Africa and parts of Asia. Congress did not enact his proposals to slash legal immigration by limiting American citizens’ ability to bring in relatives and by adding education and skill requirements, but he cut it drastically in 2020 through pandemic-related actions.Ron DeSantisHe has tried to run to the right of Trump on immigration, but is mostly aligned with him.Gov. Ron DeSantis of Florida has outlined an aggressive policy that includes mass deportations, indefinite detention of children (in violation of a 1997 consent decree known as the Flores agreement), and license to kill some border crossers.“We have to have appropriate rules of engagement to say, if you’re cutting through a border wall on sovereign U.S. territory and you’re trying to poison Americans, you’re going to end up stone cold dead,” he told Fox News, shortly after saying while in Texas that he would authorize “deadly force” against people “demonstrating hostile intent.”He also wants to end birthright citizenship for children of undocumented immigrants, an idea Mr. Trump floated in 2018 that rejects the 14th Amendment’s guarantee of citizenship to “all persons born or naturalized in the United States, and subject to the jurisdiction thereof.” Any such effort by a president would almost immediately wind up in court.Mr. DeSantis wants to finish building a border wall; require asylum seekers to stay in Mexico while awaiting hearings, as Mr. Trump did; deputize state and local officials to carry out deportations; and deploy the military to the border, which could violate a federal prohibition on using the military for civilian law enforcement. He has said he would declare a national emergency, allowing more unilateral action.Gov. Ron DeSantis of Florida held a campaign event in Eagle Pass, Texas, last month. He has tried to stake out territory to the right of Mr. Trump on some campaign platforms, including immigration.Christopher Lee for The New York TimesChris ChristieHe mostly toes the G.O.P. line, but is also critical of Trump on the issue.Former Gov. Chris Christie of New Jersey has proposed sending the National Guard to the border to stop illegal crossings and intercept fentanyl (though fentanyl mostly comes into the U.S. through official ports of entry, hidden in legitimate commerce).He has criticized Mr. Trump as all talk on border security, noting that his wall covers only a quarter of the border. But he also said on CNN last month that since the wall had been started, “you might as well finish it,” even though “I probably wouldn’t have done that at the start.” He argues that Mr. Trump erred by enacting immigration policy through executive actions that President Biden could easily undo.Mr. Christie has changed his mind on a pathway to citizenship for undocumented immigrants — in 2010, he urged Congress to create one; then, during his first presidential campaign in 2015, he said he considered it “extreme.” His campaign did not respond to a request to confirm his current position or to elaborate on what other immigration policies he supports.Nikki HaleyShe is largely aligned with the bulk of the field and supports most of Trump’s policies.When she was governor of South Carolina, Nikki Haley signed a law requiring businesses to use a federal database to check prospective employees’ immigration status, mandating that police officers check the status of some people they stopped for unrelated reasons, and making it a crime to “harbor or transport” an undocumented immigrant. She has cited this as a national model, though a judge blocked parts of the law and the state agreed to soften it.Nikki Haley has expressed support for some of Mr. Trump’s immigration policies, but not separating families.Kathryn Gamble for The New York TimesMs. Haley has also said that she wants to restore Mr. Trump’s “remain in Mexico” policy, add 25,000 Border Patrol and ICE agents, withhold funding from “sanctuary cities” that limit cooperation with immigration officials, and immediately deport migrants. But she does not support separating families, she said.Like Mr. Trump and Mr. DeSantis, she wants to limit birthright citizenship. “For those that are in this country legally, of course I think we go according to the Constitution, and that’s fine,” she told Fox News. “But it’s the illegal immigrations that we have to make sure that just because they get here, if they have a child, you’re just building on the problems.”She told CBS News that she wanted legal immigration to be based on “merit” and businesses’ needs.Tim ScottHe is largely aligned with the bulk of the field and supports most of Trump’s policies.Senator Tim Scott of South Carolina introduced legislation alongside other Republican senators this year to withhold funding from sanctuary cities and to redirect funding that Democrats had allocated for new I.R.S. agents to border security instead. Neither bill is viable in the Democrat-controlled Senate.Mr. Scott told NBC News that he supported a requirement for asylum seekers, if they cross other countries en route to the U.S. border, to request asylum in those countries before requesting it in the United States — a policy that Mr. Biden has enacted and that a judge blocked on Tuesday.In the same interview, he said he supported a border wall, new surveillance technology and an increased military presence along the border. He said he would not rule out the possibility of sending troops into Mexico to combat drug cartels.Senator Tim Scott has said that he supports a border wall, new surveillance technology and an increased military presence along the border.Travis Dove for The New York TimesLike many candidates, Mr. Scott also wants to reinstate the Title 42 policy that allowed rapid explusion of migrants on pandemic-related public health grounds. He argued in an interview with Fox News that fentanyl, rather than the coronavirus, was the public health crisis that now justified the policy.Mike PenceHe is largely aligned with the bulk of the field and supports most of Trump’s policies.Former Vice President Mike Pence said last year that he supported a return to Mr. Trump’s immigration policies, including continuing to build a border wall, banning the establishment of sanctuary cities and reinstating the “remain in Mexico” requirement for asylum seekers.He said in a CNN town hall event that he would not, however, reinstate family separation because “we got to stop putting Band-Aids on the problem.”In the same event, he called for a “guest worker” program under which people seeking jobs in agriculture and other industries could “come and for a short period of time pay taxes, participate in our economy, and go home.”Mr. Pence also vociferously opposed the Biden administration’s lifting of Title 42 and wants to reinstate it — as well as a requirement that legal immigrants demonstrate that they will not rely on public assistance.Vivek RamaswamyHe has proposed some of the most aggressive stances of any candidate.Vivek Ramaswamy has called for securing the border by any means necessary, including military force. This could violate an 1878 law that forbids the use of federal troops for civilian law enforcement, but Mr. Ramaswamy argues that securing the border isn’t civilian law enforcement.He wants to “universally” deport undocumented immigrants and opposes any path to legal residence because “we are a nation of laws,” he said at a campaign event. “That is something we cannot compromise on.”He added that, for people brought to the United States as children, he would be open to a process allowing them to return after being deported. But all legal immigration, he says, should run on a “meritocratic” points system, with lottery-based paths eliminated.His anti-immigrant language has been incendiary. On Fox News, he said citing undocumented immigrants’ economic contributions was tantamount to making economic arguments for slavery: “‘The vegetables will rot in the field, we need people to pluck our crops’ — this is a thing that Democrats were saying in the South in the 1860s to justify a different form of immoral and illegal behavior,” he said.Asa HutchinsonHe is somewhat more moderate than Trump, but still advocates strict policies.Former Gov. Asa Hutchinson of Arkansas, in a Fox News opinion essay, called for adding Border Patrol agents and authorizing murder charges against people accused of supplying fentanyl that leads to deaths. “We should ensure those who bring evil across our borders and sow criminality throughout our country are proportionately punished,” he wrote.In an interview with the New Hampshire news station WMUR, he didn’t rule out supporting a pathway to citizenship for undocumented immigrants, but said a secure border was a prerequisite for any such immigration reform. He also said that he supported a wall in some places, but that it wasn’t feasible along the full border.As governor, Mr. Hutchinson signed a law to make immigrants with federal work permits eligible for professional licenses. He also authorized the deployment of 40 Arkansas National Guard troops to the border in Texas in 2021.Doug BurgumHe expresses some more moderate views but hasn’t made detailed proposals.Gov. Doug Burgum of North Dakota has expressed support for lowering barriers to legal immigration, a stance that sets him apart from most other candidates in the field.In an interview with Forbes, he criticized the obstacles encountered by seasonal agricultural workers and prospective tech employees, saying, “We put them through two, three, four, five years of red tape, and then we let people illegally cross the southern border, so the two things juxtaposed against each other make no sense.”In the same interview, he accused President Biden of being weak on border security and said, “We can’t have a discussion in this country about legal immigration until we solve the illegal immigration.” But he has not described how to do that, and his campaign did not respond to a request for details.As governor, he signed legislation to create an Office of Legal Immigration to help North Dakota businesses hire foreign workers. He has also sent state National Guard troops to the border in Texas.Will HurdHe is on the more moderate end of the G.O.P. field.As a member of Congress, Will Hurd described a border wall as a “third-century solution to a 21st-century problem,” called the separation of migrant families “unacceptable,” and said Mr. Trump’s ban on travelers from several Muslim countries “endangers the lives of thousands of American men and women in our military, diplomatic corps and intelligence services.”He has also criticized Mr. Biden’s policies from the opposite direction, telling CBS News that the president is “treating everybody that comes into the country as an asylum seeker.”What Mr. Hurd himself would do is less clear, and his campaign did not respond to a request for information. He told NBC News that he wanted to “streamline” legal immigration, but offered no details. He has supported protections for “Dreamers” who migrated illegally as children, and he has also previously called for a new version of the post-World War II Marshall Plan to strengthen Central American economies and reduce the poverty and instability driving migration.Francis SuarezHe is on the more moderate end of the G.O.P. field.Mayor Francis X. Suarez of Miami opposes many of the far-right immigration policies outlined by many other candidates, including by his governor, Mr. DeSantis. He argued on Fox Business that the aggressive immigration bill Mr. DeSantis and the Florida Legislature had enacted was “having an adverse impact on small businesses in our state.”He said that he believed the country was “not ready” for amnesty for undocumented immigrants, but that he was open to creating some legal status that would protect them from deportation. Of actually deporting all of them, he said, “It’s not possible.”He has otherwise been vague, saying that he wants to make legal immigration “merit-based and skill-based” and that he believes he has “credibility” on the issue as a Hispanic Republican, but not proposing specific policies. His campaign did not respond to a request for details. More