What is the significance of the fact that the sedition act, passed by a federalist-dominated congress, would expire on march 3, 1801? what does this tell you about the federalists who championed the sedition act?

The Sedition Act was set to expire on March 3, 1801, which is "coincidentally" the last day of President John Adams (first and only) presidential term. The president himself was a Federalist and was heavily-backed by the Federalist-dominated Congress at that time.

Despite the criticisms that the Alien and the Sedition Acts drew, the Federalists still made use of their power (in the Congress and through the president) to take into effect such laws, which were deemed unconstitutional. The Federalists contended that they only did so in order for President Adams to fulfill his duties and obligations as president without any interference. These actions of the Federalists contributed to their losses in the elections in 1800.