should forever be prohibited in any territory which might be
obtained from Mexico by the contemplated treaty. The proviso was
written by an Ohio Democrat and was introduced in the House by
David A. Wilmot, a Pennsylvania Democrat, after whom it is known.
It passed the House by a fair majority with the support of both
Whigs and Democrats. At the time of the original introduction in
August, 1846, the Senate did not vote upon the measure. Davis of
Massachusetts moved its adoption but inadvertently prolonged his
speech in its favor until the hour for adjournment. Hence there
was no vote on the subject. Subsequently the proviso in a new
form again passed the House but failed of adoption in the Senate.

During the war the Wilmot Proviso was the subject of frequent
debate in Congress and of continuous debate throughout the
country until the treaty with Mexico was signed in 1848. A vast
territory had been acquired as a result of the war, and no
decision had been reached as to whether it should remain free or
be opened to settlement by slave-owners. Another presidential
election was at hand. For fully ten years there had been
ever-increasing excitement over the question of the limitation or
the extension of slavery. This had clearly become the topic of
supreme interest throughout the country, and yet the two leading
parties avoided the issue. Their own membership was divided.
Northern Democrats, many of them, were decidedly opposed to
slavery extension. Southern Whigs with equal intensity favored
the extension of slavery into the new territory. The platforms of
the two parties were silent on the subject. The Whigs nominated
Taylor, a Southern general who had never voted their party
ticket, but they made no formal declaration of principles. The
Democrats repeated with colorless additions their platforms of