Wisconsin governor Scott Walker said on Sunday he has no plans to alter or repeal the 14th amendment to the US constitution, which grants citizenship to those born or naturalised in the country, as Republican presidential hopefuls continued to grapple with the issue of immigration reform.

Related: ‘Anchor babies’: how the controversial term became an election talking point

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Birthright citizenship has been thrust into the limelight after Republican frontrunner Donald Trump released his immigration policy platform , in which he called for its abolition.

Walker has struggled to provide a coherent line on the issue, offering three different positions within a week. Speaking to ABC News on Sunday , he was asked if he had any plans to alter the 14th amendment.

“No,” he responded, adding: “My point is any discussion that goes beyond securing the border and enforcing laws are things that should be a red flag to voters out there.”

On Monday, however, he told reporters at the Iowa State fair the US should “ absolutely ” repeal the right. On Friday, he told CNBC he was not taking a position on the issue “ one way or the other ”.

Republican candidates have struggled with the issue both rhetorically and in terms of policy commitments. Trump has unapologetically used the controversial phrase “anchor baby” to refer to the children of non-US citizens born in America and therefore given citizenship by right, helping their parents to stay.

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Jeb Bush, Trump’s closest rival in the polls, also used the term, despite guaranteeing support for the 14th amendment and birthright citizenship. In a heated interview exchange on Thursday, the former Florida governor said: “Do you have a better term? You give me a better term and I’ll use it.”

Florida senator Marco Rubio, the son of Cuban migrants, has also committed to preserving the right. Texas senator Ted Cruz, however, said on Saturday birthright citizenship “ doesn’t make sense ”.

This split in the crowded Republican field underlines the tight line the candidates face in trying to appeal to both a conservative base and the pivotal Latino vote. An analysis conducted last month by the Latino polling blog Latino Decisions indicated that the eventual Republican presidential nominee will need between 42% and 47% of the Latino vote to win in 2016.

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During Walker’s ABC interview he recognised that his campaign, which has lagged in recent polls , was in need of an injection of passion. The governor also roundly criticised Republican colleagues in Washington for failing to repeal President Obama’s Affordable Care Act, drew on his record fighting union leaders in Wisconsin and referenced an instance at the Iowa state fair when he refused to bow to some in the crowd who heckled him.

“People want to see what they saw at the Iowa state fair,” he said. “When we had protesters, one of them tried to come up on the stage and I said: ‘I’m not intimidated by you, sir.’ I’m not intimidated by the left. I’m not intimidated by the special interests from Washington. I’m certainly not intimidated by the big-government union bosses.”

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Related: Undocumented, Asian and taking up arms in the immigration fight – finally

Trump had appeared earlier on the same show, to accuse Walker of copying his brand of politics.

“I’m honoured that he wants to copy me, he’s a nice man. But his state has not performed well,” Trump said with reference to Walker’s economic record. Trump has frequently accused Walker of presiding over a $2.2bn deficit in Wisconsin, where the state legislature passed a two-year balanced budget last month .

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The billionaire businessman later phoned in to CBS , where he was asked if he was prepared to accept donations from wealthy backers. He indicated that he would, marking a departure from previous campaign rhetoric, but said anyone preparing to offer donations should not expect any favours in return.

“I don’t want any strings attached,” Trump said. “I turned down $5m from a very important lobbyist because there are total strings attached to a thing like that.

“He’s going to come to me in a year or two years,” he added. “And he’s going to want something for a country that he represents or a company that he represents. That’s the kind of money I won’t take.”

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