By Thursday afternoon, the indictment and its implications were a hot topic for Washington’s lucrative lobbying and communications consulting industry.

The charges will prompt even more diligent review of possible compliance obligations by consultants who represent foreign clients, said Thomas J. Spulak, a partner at the King & Spalding law firm who advises on lobbying compliance.

“It’s pretty significant,” he said. “It’s not just trying to influence the government; it’s trying to influence the American public.” He added, of Mr. Craig’s case, “If they can establish the facts, then I think it’s a pretty serious violation.”

Mr. Craig’s indictment also attracted notice because he is the first person who made his name in Democratic Party politics to be charged in a case linked to the special counsel’s investigation. An Ivy League-educated lawyer, Mr. Craig held prominent positions in the administrations of President Bill Clinton and President Barack Obama.

The charges “undermine the narrative of President Trump and congressional Republicans that the Mueller probe was a Democratic witch hunt meant to bring down Trump and the G.O.P.,” said Carl Tobias, a professor at the University of Richmond School of Law.

The indictment said Mr. Craig “did not want to register as an agent for the government of Ukraine” partly because he believed doing so would make it less likely that he and others at his firm at the time, Skadden, Arps, Slate, Meagher & Flom, would be appointed to federal government posts. Mr. Obama had put rules in place restricting the work that former lobbyists could do in his administration.