US District Judge Leo Sorokin in Boston issued the ruling, opens new tab in a lawsuit filed by 20 Democratic state ​attorneys general challenging a fee Trump announced in September ​that dramatically raised the cost of obtaining H-1B visas.

The ⁠H-1B programme offers 65,000 visas annually, with another 20,000 visas ​for workers with advanced degrees, approved for three to six years. ​Employers seeking a visa for a foreign worker before Trump’s proclamation typically paid about $2,000 to $5,000 in fees depending on various factors.

The increase in fees ​has discouraged H-1B visa requests, according to court filings. As ​of February 15, US Citizenship and Immigration Services had received just 85 ‌payments ⁠of the $100,000 fee, the administration said in a March filing.

The administration argued that the fee constituted a monetary penalty that the president had lawful authority to impose under federal immigration ​law to restrict ​the entry of ⁠certain foreign nationals.

But Sorokin, who was appointed by Democratic President Barack Obama, concluded that ​the fee was not a penalty but a ​tax that ⁠the Republican president lacked any authorization from Congress to issue.

“Here, the substance and application of the $100,000 payment reveal that it is ⁠a tax, ​regardless of what the payment is ​called,” he wrote.

The White House did not immediately respond to a request ​for comment.