What was the primary reason for the decay of the Federalist party during Adams' presidency?

The primary reason for the decay of the Federalist party during Adams' presidency was the opposition to war, particularly the party's stance during the Quasi-War with France. The Federalists, who had a strong inclination toward a pro-British foreign policy, faced significant backlash for their handling of foreign relations, which critics perceived as leaning towards militarization and conflict. The Federalists' opposition to war created a perception that they were out of touch with public sentiment, especially as many citizens, who were supportive of maintaining peace, viewed the potential for war as unnecessary and detrimental.

Public opinion began to shift towards the Democratic-Republicans, who were more favorable to France and generally advocated for a more diplomatic approach. This shift was exacerbated by the Federalists' imposition of the Alien and Sedition Acts, which many viewed as an overreach and an infringement on personal liberties. The culmination of these factors significantly weakened the Federalist party's influence and popularity during and after Adams' presidency, paving the way for a Democratic-Republican dominance in American politics.