Liberty and slavery cannot live in juxtaposition." He spoke out of the fullness of his own experience.

A thoroughly trained lawyer and statesman, well acquainted with the trend of public sentiment in both North and South, he was fully persuaded that the new pro-slavery crusade against liberty boded civil war.

He knew that the white men in North and South would not, without a struggle, consent to be permanently deprived of their liberties at the behest of a few Southern planters.
Being himself of the slaveholding class, he was peculiarly fitted to appreciate their position.

To him the new issue meant war, unless the belligerent leaders should be shown that war was hopeless.

By his moderation in speech, his candor in statement, his lack of rancor, his carefully considered, thoroughly fair arguments, he had the rare faculty of convincing opponents of the correctness of his own view.
There could be little sympathy between Birney and William Lloyd Garrison, whose style of denunciation appeared to the former as an incitement to war and an excuse for mob violence.