Can you be more specific here? How do you define "overthrow"? Do you mean attempts to replace the federal government in its entirety, or do you mean to simply replace the power of the federal government in a more limited fashion? Depending on your definition, something as small as a nullification movement could be considered an attempt to overthrow the (power of, and therefore the actual) government. A bit further up that chain might be a secessionist movement. Where would you draw the line? I ask only because this would definitely change the answer.