In a surprise turn of events Friday, President Donald J. Trump announced the revocation of a controversial executive order aimed at the global law firm Paul, Weiss, Rifkind, Wharton & Garrison LLP, citing what he described as the firm’s “remarkable change of course.

Fears that competitors could take its top rainmaking talent added to the law firm’s worries about a Trump executive order that targeted it.

On Friday, more than 500 firms and law offices from around the country signed onto a brief urging a judge to permanently block the order. The firms, in their filing, call the order a “grave threat to our system of constitutional governance and to the rule of law itself.”