Why was Alexander Hamilton for the Alien and Sedition act?

Answer 1

In the summer of 1798, the United States was close to war with France. Many members of the Federalist Party, including President John Adams and Federalist leaders in Congress, not only believed that their Democratic-Republican opponents were pro-French, but that their vocal opposition to administration policies was dangerous to the country's security. Therefore, to silence (as well as to weaken) the Democratic-Republican party, Congressional Federalists passed four statutes which are collectively known as the Alien and Sedition Acts.

Answer 2

The Federalist political party, of which Hamilton was a member, was losing popularity. The Federalists feared they would lose the coming elections. They argued, and most honestly believed, that the opposing views were dangerous. By silencing their opposition, the Federalists believed nobody could oppose them in the coming elections without being branded a traitor and arrested.

However, the people were so angry at the legislation that opposition to the Federalists exploded. Virginia and Kentucky went so far as to pass resolutions nullifying the Federal law (they passed laws saying that the federal law had no effect in their states). The laws were repealed, but the damage was done. The Federalists were basically destroyed as a party and never held national power again.