In August 1920, Tresca became involved tangentially in the Irish War of Independence. As Sidney Czira, secretary of Cumann na mBan in New York, and sister of Grace Gifford, later recalled, "Picketing of the British Embassy in Washington had been going on from 1916 onwards and I remember a very successful picketing that was undertaken as a protest in New York against the British arrest of Dr. Mannix in August 1920. This latter picketing was largely the work of an Italian called Carlo Tresca, a personal friend of the well-known Irish-American family of Flynn, who were great friends of James Connolly. Tresca had great influence among the sea-faring fraternity and suggested that we should call out the seamen from the British ships as a protest against the arrest of Dr. Mannix. This was done by pickets walking on the docks with placards, calling on the men to leave the ships. So far as I was concerned, this was rather an amusing incident, because I had a placard which read something like this, "Hear the call of the blood and refuse to work on British ships". I realised that the call of the blood was addressed to Greeks, Italians, Lascars, etc., and when they saw a young woman with a placard they came up to enquire what the strike was about. My efforts to translate "Hear the call of the blood" into Italian were funny, but I found one word which they all seemed to know was "tyranny - Irlanda", and smiling and nodding, they would all walk away. The picketing was extremely effective because when we were holding our meetings it was a thrilling sight when, from time to time, we would hear the march of feet and the crew of some ship would come marching into the room. We found out subsequently that Tresca, who had organised them, was generally supposed to be an anarchist! Of course, there were extremely severe penalties under American law for behaviour of this kind."