He argued that the political reasons for union were no less imperative: the need of ending the fatal deadlock in the Canadas, the responsibility that rested on the colonies for the shouldering of some imperial burdens, and the immeasurable benefits that would accrue to all the colonies in pooling their common resources and working for common ends. With the inspiring vision of the new nationality, he looked forward to the attainment of a mental union, in which public men from all the colonies might rise from the cramping restraints of local politics and parish business to the expanding affairs of a growing nation. None the less he did not presume that colonial union would weaken the imperial tie. On the contrary, it would strengthen it, and through it the British North American nationality would be kept in contact with European civilization. As in his former address McGee emphasized the argument of defence. "I said in this House, during the session of the year 1861, that the first gun fired at Fort Sumter had a message for us. I was unheeded then; I repeat now that every one of the 2700 guns in the field, and every one of the 4600 guns afloat, whenever it opens its mouth, repeats the solemn warning of England--prepare." Intimate observation of American politics had convinced McGee that aggression from the United States was an imminent danger, and the confederation of the colonies was the best precautionary measure of defence. He was confident that the terms of the constitution fashioned by the Quebec Conference satisfied colonial needs, and was "eminently favourable to liberty, because local affairs are left to be dealt with by local bodies and cannot be interfered with by those who have no local interest in them, while matters of a general character are left exclusively to a general government". After the stormy battle of a month, the resolutions were carried. The Canadas had accepted the projected confederation. But McGee did not relax his efforts to enlighten public opinion on the issue. In the same year he published a little book, _Notes on Federal Governments Past and Present_, outlining for colonial readers the experiments in federal government from the Aetolian and Achaian leagues of ancient Greece to the New Zealand confederation. He also published a collection of speeches on British American union, which remain the most substantial evidence of how earnestly and ably he had pleaded his cherished cause. But it was chiefly from the platform that he shaped the public mind. His oratory had now reached an impressive maturity, and the reminiscences of all who heard him at the time agree as to the charm and power of his spoken words.