The issuance this week of new guidelines on immigration by the US department of homeland security marks the latest step by US president Donald Trump’s administration to clamp down on illegal immigration – one of the president’s key campaign promises.

While officials attempted to assuage fears among immigrant communities, insisting the measure did not intend to produce “mass deportations”, fears among the undocumented Irish community as well as the millions of other unauthorised immigrants living in the US have been raised.

Though notoriously difficult to estimate, about 50,000 Irish citizens are living in the US illegally.

Most of these overstayed their legal visas; others entered the country on holiday and stayed, with many going on to have children who are US citizens.

One of the many contradictions of the US immigration system is that many Irish who are illegally residing in the US have been working and paying taxes in the US for years – for example, by continuing to use social security numbers legally assigned during J1 visa periods.

Tax revenue

According to a study by the Washington-based Institution on Taxation and Economic Policy last year, the 11 million undocumented immigrants currently living in the US collectively pay $11.64 billion in state and local taxes each year.

Unsurprisingly then, analysts estimate that the net cost to the US economy of a major immigration clampdown would be enormous. According to one study by the by the National Bureau of Economic Research, President Trump’s immigration policy could cost the economy $5 trillion over 10 years.

The White House this week argued that the new guidelines were simply implementing laws already there. “The law is the law,” press secretary Sean Spicer said as he faced questions about the measure, though he added that the president wanted to “take the shackles off” of the nation’s immigration enforcers who had been unable to do their jobs because of various carve-outs introduced by the Obama administration.

His words have sparked alarm bells among immigration lobby groups, who fear that immigrants could be rounded up without warning, such as the case of a 35-year-old Mexican mother of two who was deported earlier this month from Arizona, having moved to the US when she was 14.

Ciaran Staunton, chair of the Irish Lobby for Immigration Reform, has played down the threat, however, pointing out that, while president Obama was keen to talk down his very extensive measures on deportation, President Trump is more interested in publicising the measures to his core supporters.

“Irish who are undocumented should not make any hasty decisions based on what they have been hearing over the last week or so,” he said. “First and foremost it must be remembered that the number-one target is criminal illegals, who number approximately 800,000 according to some estimates. The manpower needed to follow up this first phase is going to be enormous. For example, it took Obama two terms to deport 2½ million people.”

Border security

Among the main changes announced this week are the deployment of an additional 15,000 immigration officials and border security staff, to help speed up the rate of deportations and expedite existing cases that are stuck in the courts. But there are also other concerning measures contained within the two memos issued on Tuesday, including the right of immigration officials to bypass court hearings in some cases.

The department of homeland security is also hoping to revive a previous measure to help enlist the support of police officers to deal with deportation, though most police forces in the US are still employed by the city or state.

While Tuesday’s revised guidelines have renewed the focus on Trump’s immigration policy,there is more to come, with a second executive order on immigration expected as early as this week.

Mr Spicer also did not rule out measures on legal immigration, for example a revision of the H 1B visa which allows US companies to hire foreign workers temporarily.

Just a month in office, President Trump has already made good on his promise to tackle immigration. Many immigrants living in the US are hoping that this is not a taste of things to come.