Final answer:
The Sedition Act of 1798, expiring on March 3, 1801, is significant because it was intended to suppress Republican opposition during John Adams's presidency and reflected Federalist concerns over the impending election. It criminalized criticism against the government, thus infringing on free speech and contributing to the historical debate on civil liberties. Its expiration marked the transition to Thomas Jefferson's presidency and the rise of the Republican Party.
Step-by-step explanation:
The significance of the fact that the Sedition Act, passed by a Federalist-dominated Congress, would expire on March 3, 1801 is that it coincided with the end of John Adams' presidency and the beginning of Thomas Jefferson's presidency. The Sedition Act was a controversial law that limited freedom of speech and the press, and it was seen as an attempt by the Federalists to suppress their political opponents, particularly the Republicans.
By setting the expiration date of the Sedition Act to coincide with the change in the presidential administration, it provided an opportunity for the incoming Republican administration to repeal the act and restore the liberties that had been curtailed.