His attitude at this time, in opposition to any further acquisition of territory on any terms, was strong and determined, but his policy was a terrible confession of weakness.

It amounted to saying that we must not acquire territory because we had not sufficient courage to keep slavery out of it.

The Whigs were in a minority, however, and Mr.
Webster could effect nothing.

When the Wilmot Proviso came before the Senate Mr.Webster voted for it, but it was defeated, and the way was clear for Mr.Polk and the South to bring in as much territory as they could get, free of all conditions which could interfere with the extension of slavery.
In September, 1847, after speaking and voting as has just been described in the previous session of Congress, Mr.Webster addressed the Whig convention at Springfield on the subject of the Wilmot Proviso.

What he then said is of great importance in any comparison which may be made between his earlier views and those which he afterwards put forward, in March, 1850, on the same subject.