What was the relationship between the louisiana purchase and political power?

The relationship between the Louisiana Purchase and political power was that it was seen as unconstitutional (and the Federalists argued this) to acquire this territory which spanned a huge region across the United States and Canada, but since Thomas Jefferson (who was then the President) had the final say, he decided this was because he had the most political power, so this showed he felt above the Constitution of the United States, because he had treaty power.