But for a time there was no need of additional territory for that already hers stretched from the Atlantic to the Rocky Mountains, two-thirds of the way from ocean to ocean.

Her population was growing fast.

But four millions at the time of the Revolution, there were thirteen millions in 1830, and of these nearly a third were already across the Appalachian range and were constantly pressing on towards new lands in the South and West.

The Monroe Doctrine was the first definite notice given to Europe of America's preconceived "destiny," but the earlier realization of that destiny took place on lines of expansion within her own boundaries.

To this there could be no governmental objection, whether by Great Britain or any other nation.
But when in the decade 1840 to 1850, the United States, to the view of British statesmen, suddenly startled the world by entering upon a policy of further territorial expansion, forsaking her peaceful progress and turning toward war, there was a quick determination on a line of British policy as regards the American advance.