“These tariffs are particularly fraught for an industry like aerospace that has been duty-free for decades,” said Bruce Hirsh, a trade policy expert at Capitol Counsel, a lobbying firm in Washington, which has aerospace clients. “Parts are coming from everywhere.”

As Canada prepared to swear in a new prime minister amid an escalating trade war with the Trump administration, the country’s provinces have turned to K Street for help finding leverage to ride out the storm, according to documents filed with the Justice Department. Several weeks before Trump took office, Capitol Counsel announced its own cross-border partnership with the Canadian firm Rubicon Strategy Inc.

The American Football Coaches Association, whose 11,000 members coach players from high school to the NFL, has tapped Capitol Counsel to give the profession a broad and unified voice as the debate in Washington plays out over the coming years.