Why did Federalists oppose the Louisiana Purchase and what did they plan to do about it?

Some of the Federalists did not like the idea of the Louisiana Purchase because it was likely to help their political enemies and hurt themselves.  However, we should not overstate the opposition to the purchase.  Major Federalist figures like Alexander Hamilton and John Adams actually did support the purchase because they wanted to strengthen the nation as a whole.  However, there were some Federalists who felt that the purchase was a bad idea because it would strengthen Thomas Jefferson and his political party.

The main reason why the Federalists did not like the Louisiana Purchase was that it would add more land to the South.  The South was not an area with many Federalists.  Because of this, the purchase was likely to add to the political power of the Jeffersonians.  In the short term, it was also likely to get Jefferson reelected.  Finally, the Federalists were worried that the purchase would bring in huge new areas of land that could be settled by the small farmers that were major supporters of Jefferson’s party.

Some Federalists talked of secession over this issue, but the talk really did not get very far.  So, to the extent that Federalists disliked the Louisiana Purchase, it was for political reasons and they did very little to try to prevent the purchase.