Why did the Federalists fall from power in late 1790s?

I would say that the Federalists fell from power because their policies got to be unpopular among the people.  there were quite a few policies of theirs that contributed to them losing power.

First, people were unhappy about the Alien and Sedition Acts.  Those laws made it seem as if the Federalists were against freedom.

Second, people were unhappy about the power of the federal government.  They worried that the Federalists wanted a monarchy and they pointed to things like the Whiskey Rebellion as proof that this was the case.

Finally, people were unhappy because they felt that Jay's Treaty had given up too much to the British.