London | Edwin Vermulst, a trade lawyer in Brussels, did not think twice before he agreed to write an article for Huawei, the Chinese telecommunications giant, that would criticise a Belgian policy that threatened to box the company out of lucrative contracts. He had worked with the company for years.

After the article was published December 17 on a Dutch-language website, he moved on to other work. “That was the beginning and end of my involvement,” he said.