Why did some Federalists respond to the Louisiana Purchase by plotting to secede from the Union?

They opposed it because they suspected that new states formed in the Louisiana Territory would be Republican and thus jeopardize the balance of power. Some Federalists planned to secede from the Union.

you can talk about what you learned about them. and you can talk about what happened on you're journeys with them. and then you can put all of the thing you learned about them in you're diary.