In his day he was considered one of the best orators in Newfoundland. Upon his return to the island he embarked on a campaign opposing the
Commission of Government which had been brought about in 1934. He was elected to the
Newfoundland National Convention formed in 1946 to consider the
dominion's future. In 1947, Cashin was one of the members of the National Convention's delegation to London charged with finding out what assistance the British government was prepared to give Newfoundland in the future including development aid or cancellation of the dominion's debt. The results were disappointing as Britain refused to give Newfoundland any promise of financial assistance. Nevertheless, he opposed
Joey Smallwood's campaign to join
Canadian Confederation and became the leader of the
Responsible Government League leading it into the 1948
referendums on Newfoundland's status. On May 19, 1947, Cashin delivered this speech to the National Convention regarding the future of
Newfoundland. Cashin was unsuccessful in the referendum, though he was convinced that he had actually won and that the referendum result had been falsified by the British. ==Later political career==