A federal judge on Wednesday issued a temporary restraining order against President Donald Trump's executive order targeting a law firm over its work for Hillary Clinton's 2016 election campaign.

WASHINGTON—A federal judge blocked most of a White House executive order punishing Perkins Coie, saying the administration had put itself at odds with the First Amendment by targeting the law firm based on President Trump’s dislike of its work for his political opponents.

The president’s use of government power to punish firms is seen by some legal experts as undercutting a basic tenet: the right to a strong legal defense.