Federal Judge Arthur J. Schwab issued a scathing memo Tuesday calling President Obama’s executive order on amnesty unconstitutional, Washington Times reports.

Schwab is said to have accused Obama of “usurping” and “dismantling” Congress’s power.

The judge was presiding over a deportation case in Pennsylvania when the ruling was made. The Times is quick to note that the ruling does not overturn the president’s executive order, but “serves as a warning shot” to other cases as they make their way into courts.

More from the Times:

A federal judge has found parts of President Obama’s new deportation amnesty to be unconstitutional, issuing a scathing memo Tuesday accusing him of usurping Congress’s power to make laws, and dismantling most of the White House’s legal reasoning for circumventing Congress.

Judge Arthur J. Schwab, sitting in the western district of Pennsylvania, said presidents do have powers to use discretion in deciding how to enforce the law, but said Mr. Obama’s new policy goes well beyond that, setting up a full system for granting legal protections to broad groups of individuals. He said Mr. Obama writing laws [is] a power that’s reserved for Congress, not the president.

‘President Obama’s unilateral legislative action violates the separation of powers provided for in the United States Constitution as well as the Take Care Clause, and therefore is unconstitutional,’ Judge Schwab wrote.

The judge also said the policy allows illegal immigrants ‘to obtain substantive rights.’