Washington, Dec 17 (IANS/EFE): A federal judge in Pennsylvania Tuesday ruled unconstitutional President Barack Obama's recent executive action to temporarily protect from deportation more than five million undocumented foreigners.

Judge Arthur Schwab, appointed to the bench by former Republican president George W. Bush, justified his ruling on the legality of the presidential decree because the accused in a driving under influence (DUI) case, 42-year-old Elionardo Juarez-Escobar, could -- in his judgment -- benefit from Obama's executive action.

This is the first court decision against regularising the status of undocumented immigrants announced by Obama last month, a measure that has spurred Republican opposition and opened a new inter-party battle front in Congress, which will pass to full conservative control in January.

Since the case in question is an individual case that has no direct relationship with the president's executive action, legal analysts consulted by US media outlets say that the ruling will not have any immediate impact.

Juarez-Escobar was deported in 2005 but came back to this country illegally and was arrested this year while driving under the influence of alcohol.

Schwab's argument for ruling on the presidential action is that Juarez-Escobar could avoid deportation thanks to Obama's measures.

The judge said that Obama "violated the separation of powers" with his unilateral action, which he said was "unconstitutional" because it enables a broad group of people to receive different treatment on the basis of "arbitrary" classifications rather than on a case-by-case basis.

Lawyers with the US government, however, told the magistrate that the defendant, who pleaded guilty to re-entering the country, was not eligible for relief under Obama's measures because the executive order does not affect criminal proceedings.

There are some 11.3 million undocumented foreigners living in the US, according to government estimates, and more than half of them are Mexicans.

Most of those who stand to benefit from Obama's executive action -- 3.7 million people in all -- have children who are US citizens or have permanent residence and have lived here for at least five years, according to the Migration Policy Institute.

The other 1.5 million people who will benefit from Obama's measures will do so as a result of the broadening of Deferred Action, a measure that since 2012 has prevented the deportation of more than 580,000 young people who were brought to this country as children.