The telegraph, the railway, and the resulting industrial development proved great nationalizing influences.

They served also to give increased emphasis to the contrast between the industries of the free and those of the slave States.

The Census of 1850 became an effective anti-slavery argument.
The telegraph also gave new life to the public press.

The presidential campaign of 1848 was the last one in which it was possible to carry on contradictory arguments in support of the same candidate.

If slavery could not endure the test of untrammeled discussion when there were no means of rapid intercommunication such as the telegraph supplied, how could it contend against the revelations of the daily press with the new type of reporter and interviewer which was now developed?
It is a remarkable coincidence that in the midst of the passing of the old and the coming in of the new order there should be a change in the political leadership of the country.