They were not figure-heads in the transaction.

They were the vital, moving forces.
Victories with Which Diplomats Have no Concern.
Just the contrary is true of cases like that of the conquest of Texas.
The Government of the United States had nothing to do with winning Texas for the English-speaking people of North America.

The American frontiersmen won Texas for themselves, unaided either by the statesmen who controlled the politics of the Republic, or by the soldiers who took their orders from Washington.
Victories of Mixed Nature.
In yet other cases the action is more mixed.

Statesmen and diplomats have some share in shaping the conditions under which a country is finally taken; in the eye of history they often usurp much more than their proper share; but in reality they are able to bring matters to a conclusion only because adventurous settlers, in defiance or disregard of governmental action, have pressed forward into the longed-for land.
In such cases the function of the diplomats is one of some importance, because they lay down the conditions under which the land is taken; but the vital question as to whether the land shall be taken at all, upon no matter what terms, is answered not by the diplomats, but by the people themselves.
It was in this way that the Northwest was won from the British, and the boundaries of the Southwest established by treaty with the Spaniards.
Adams, Jay, and Pinckney deserve much credit for the way they conducted their several negotiations; but there would have been nothing for them to negotiate about had not the settlers already thronged into the disputed territories or strenuously pressed forward against their boundaries.
Louisiana Really Acquired by the Western Settlers.
So it was with the acquisition of Louisiana.

Jefferson, Livingston, and their fellow-statesmen and diplomats concluded the treaty which determined the manner in which it came into our possession; but they did not really have much to do with fixing the terms even of this treaty; and the part which they played in the acquisition of Louisiana in no way resembles, even remotely, the part which was played by Seward, for instance, in acquiring Alaska.