Mr. Webster spoke with great force and in a tone of solemn warning against the whole policy of territorial aggrandizement.  He denounced all that had been done in this direction, and attacked with telling force the Northern democracy, which, while it opposed slavery and favored the Wilmot Proviso, was yet ready to admit new territory, even without the proviso.  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.  The passage is as follows:—­

“We hear much just now of a panacea for the dangers and evils of slavery and slave annexation, which they call the ‘Wilmot Proviso.’  That certainly is a just sentiment, but it is not a sentiment to found any new party upon.  It is not a sentiment on which Massachusetts Whigs differ.  There is not a man in this hall who holds to it more firmly than I do, nor one who adheres to it more than another.

“I feel some little interest in this matter, sir.  Did I not commit myself in 1837 to the whole doctrine, fully, entirely?  And I must be permitted to say that I cannot quite consent that more recent discoverers should claim the merit, and take out a patent.

     “I deny the priority of their invention.  Allow me to say, sir, it
     is not their thunder.

“There is no one who can complain of the North for resisting the increase of slave representation, because it gives power to the minority in a manner inconsistent with the principles of our government.  What is past must stand; what is established must stand; and with the same firmness with which I shall resist every plan to augment the slave representation, or to bring the Constitution into hazard by attempting to extend our dominions, shall I contend to allow existing rights to remain.

     “Sir, I can only say that, in my judgment, we are to use the first,
     the last, and every occasion which occurs, in maintaining our
     sentiments against the extension of the slave-power.”