Why do you think Lewis and Clark continued into the Oregon territory when the Louisiana territory ended at the rocky mountains?

President Thomas Jefferson commissioned the expedition shortly after the Louisiana Purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an American presence in this territory before Britain and other European powers

To have a bunch of countries to team up, and communicate not let the communist break them apart and take over the world