The discussion was conducted by Southern men on one side and by Northern men on the other,--the first division of the kind in the Democratic party.

Slavery was the ominous cause! The South triumphed and the rule was fastened upon the convention.
Immediately after this action Mr.Van Buren received a majority of the votes on the first ballot, and it was not unnaturally charged that many of those supporting him must have been insincere, inasmuch as they had the full right, until self-restrained by the two-thirds rule, to declare him the nominee.

But this conclusion does not necessarily follow.

Mr.Van Buren had been nominated in the National Democratic Conventions of 1835 and 1839 with the two-thirds rule in operation; and now to force his nomination for a third time by a mere slender majority was, in the judgment of wise and considerate party leaders among his own friends, a dangerous experiment.

They instinctively feared to disregard a powerful and aggressive minority stubbornly demanding that Mr.Van Buren should be subjected to the same test which his friends had enforced in previous conventions.
Their argument was not satisfactorily answered, the rule was adopted, and Mr.Van Buren's fate was sealed.
CALHOUN DEFEATS VAN BUREN.
The Southern men who insisted upon the rule had the courage to use it.