The chairman of a prominent law firm who cut a deal with President Donald Trump last week to avert the consequences of a White House executive order told colleagues in an email Sunday that he did so because the order “could easily have destroyed our firm” and put it out of business. The message from Brad Karp offers the most detailed public explanation yet about the decision to make significant concessions to the White House in the face of an executive order that targeted his firm, Paul, Weiss, Rifkind, Garrison & Wharton. The order, the latest in a series of similar actions targeting law firms whose lawyers have performed legal work that Trump disagrees with, threatened the suspension of security clearances for Paul Weiss attorneys as well as the termination of any federal contracts involving the firm.