A federal judge on Monday struck down a US$100,000 fee that US President Donald Trump imposed on new H-1B visas for highly skilled foreign workers, concluding that it constituted an unlawful tax that Congress never authorised. US District Judge Leo Sorokin in Boston issued the ruling 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, which tech companies in particular rely...