Why is the designation of conspiracy as a crime sometimes criticized as a threat to first amendment freedom

The First Amendment states that: Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.

So, some scholars and lawyers believe that the crime of conspiracy infringes on "the right of the people peaceably to assemble."

Conspiracy is, essentially, the crime of association and can be used to keep unpopular groups from association with each other. Conspiracy has been used time and again in history to shut down both good AND bad groups but it does limit ones ability to peaceably assemble.

b or c im pretty sure

missouri compromise of 1820 which prohibited slavery