Twitter is growing its Washington office with a new hire aimed at working on public policy issues.

According to The Hill Twitter has just hired William Carty, a long-time Republican aid, to expand its Washington presence.

Carty joins Colin Crowell, hired in August 2011, as the newest member of Twitter’s now-two-person public policy team.

Both Carty and Crowell are responsible for public policy issues related to Twitter. Crowell has been working on Twitter’s global public policy team for the past year, while Carty will head up Twitter’s efforts aimed directly at Washington when he starts next month.

Carty’s job will see him educate lawmakers on how to use Twitter, as well as monitor policies that may affect the company.

He’s not an official lobbyist, but according to The Hill, a Twitter spokesperson acknowledged that Carty might register as one if his activities require him to. This would be Twitter’s first lobbyist, joining the likes of Facebook and Google lobbyists trying to persuade Washington to keep Silicon Valley in mind when drafting their policies.

Prior to his new job with Twitter, Carty had been working for the Republican party on the Senate Commerce, Science and Transportation Committee this past year. And before that he had spent about ten years on the House Energy and Commerce Committee, working as an aide.

Twitter has a total of nine employees in Washington: three on their media team, four in sales, and now two in charge of public policy.

(Handshake image via Shutterstock)