The Washington Post reports: Twitter filed a lawsuit Thursday against the U.S. Department of Homeland Security, asking the court to prevent the department from taking steps to unmask the user behind an account critical of the Trump administration.

The tech company said that allowing DHS access to that information would produce a “grave chilling effect on the speech of that account,” as well as other accounts critical of the U.S. government. The case sets up a potential showdown over free speech between Silicon Valley and Washington.

According to Twitter’s court filings, Homeland Security is “unlawfully abusing a limited-purpose investigatory tool” to find out who is behind the @ALT_USCIS account. Its Twitter feed has publicly criticized the administration’s immigration policies, particularly the actions of the U.S. Citizenship and Immigration Services (USCIS) division of Homeland Security. [Continue reading…]