Ted Cruz noticeably toughened his stance on immigration this week, vowing to deport the estimated 12 million illegal immigrants currently living the US, and using a story of “Tommy O’Malley from Co. Cork” as an example of the way in which he’ll use Immigration and Customs Enforcement to track down illegal immigrants in their homes.

This is despite the Texan senator, who has Irish roots on his mother’s side, previously stating that the rounding up of all the country’s undocumented was impractical and authoritarian.

Following in the footsteps of Republican front-runner Donald Trump, and coming just a day before Trump’s third consecutive victory, this one in Tuesday’s Nevada caucus, Cruz outlined a tougher stance on immigration, promising to round up and forcibly deport all the undocumented people living in the US, including the estimated 50,000 Irish living in the US illegally.

Speaking on the Fox News program “The O’Reilly Factor” on Monday evening, Cruz went one step further than the billionaire front-runner, in fact, by announcing that he would not allow those who had previously lived in the country illegally to re-enter the US by legal means after their deportation. He claimed that Trump’s policy involved allowing those who previously broke US immigration laws to return to the US on another visa.

Read more: Why GOP’s Ted Cruz is no John F Kennedy

Fox commentator and self-proclaimed Irish American Bill O’Reilly pressed Cruz on these policies during the appearance, asking the conservative senator how he would deal with a fictional Irishman “Tommy O’Malley” who had settled illegally in New York State.

“So Tommy O’Malley from Co. Cork in Ireland is over here and he overstays his visa and he has got a couple of kids and he has settled into Long Island,” O’Reilly put to the first-time Senator.

“And you, President Cruz, are going to send the Feds to his house, take him out and put him on a plane back to Ireland?”

Cruz, who only took a feeble third place in Nevada on Tuesday, replied: “You better believe it.”

“Right now, we actually can’t do that because we don’t have a biometric exit-entry system so we don’t know when, in your example, Tommy goes home.”

Cruz continued to pledge that during his Presidency he would introduce a system by which authorities would be informed as soon as an immigrant overstayed their visa, allowing federal agents to travel to their homes and begin deportation proceedings.

Challenging Cruz’s ability to put these policies into practice, O’Reilly questioned the Senator on whether a US federal court would not be able to put a stop to him immediately deporting said “Tommy O’Malley.”

“I spent my entire life as a constitutional lawyer,” 45-year old Cruz answered.

“So federal law right now requires a biometric exit-entry system on visas. The Obama administration refuses to enforce federal law.

“As president I will put that in place so we will know the day someone overstays their visa and be able to send law enforcement to apprehend them and send them home.”

Cruz’s new hard stance on immigration appears to have evolved from Trump’s success in New Hampshire and South Carolina where his tough approach toward illegal immigrants appealed to voters.

The Texan senator is now following suit, despite showing reluctance to support Trump’s policy as recently as last month and despite his family's own immigration history.

The Canadian-born son of a Cuban immigrant and a mother with Irish and Italian roots, Cruz argued in an interview with CNN in January that going to the homes of illegal immigrants and instantly deporting them was not the best way in which to enforce immigration law.

Read more: “Black Irish” Ted Cruz may face birther questions of his own

At the time he argued that only those apprehended would be deported.

“No, I don't intend to send jackboots to knock on your door and every door in America. That's not how we enforce the law for any crime,” he told CNN.

"We don't have any system that knocks on the doors of every person in America. We also don't have people going door-to-door looking for murderers. We don't live in a police state. We do have law enforcement."

Donald Trump has since dismissed Cruz’s remarks that he would allow those deported to re-enter the country.

Ted Cruz said on @oreillyfactor that illegals sent out of country by my administration would come right back as citizens. Another lie-crazy!

— Donald J. Trump (@realDonaldTrump) February 23, 2016

Marco Rubio, who came in second in Nevada and is Cruz’s closest rival, although still some 20 points behind Trump, slammed Cruz’s change of position, stating that the hardening of policy was only happening as his campaign is “under duress.”

"There are people that are going to be deported. There are people who are being deported now. If you're here illegally in this country and you have a deportation order, you are going to be deported, especially if you are a dangerous criminal," Rubio said.

“But I don't think this country is going to support – nor do I think we need to pursue – a military-style roundup of people in America."

It is estimated that there are currently 50,000 undocumented Irish living in the US, 30,000 in the New York city area alone.

Cruz has often referred to the “Irish wit” of his political hero Ronald Reagan while on the campaign trail and spoke to the Irish Times earlier in the year about his own Irish connections.

When asked if he liked to use his Irish roots to his advantage in his political career, the Texan told the Irish paper: “I certainly do my best. Being half-Irish, that is a part I need to channel more and more every day.”