Filing a trademark application with the United States Patent and Trademark Office (USPTO) starts a legal proceeding that is governed by U.S. law. While you may represent yourself in this legal proceeding, most applicants hire attorneys who specialize in trademark matters to represent them. Many continue to use attorneys after their trademarks are registered.
Title: Requirement of U.S. Licensed Attorney for Foreign Trademark Applicants and Registrants Abstract:The United States Patent and Trademark Office (USPTO) proposes to amend its rules to require foreign trademark applicants and registrants to be represented by a U.S. licensed attorney, i.e. an attorney in good standing of the bar of the highest court of a State in the U.S. (including the District of Columbia and any Commonwealth or territory of the U.S.) to file trademark documents with the USPTO.
情報源: View Rule