While pee pee-boy was tying up the news with Wienergate back back in in June, the American president made a typical Obamian move; he signed Executive Order 13575. This created a "White House Rural Council". The council was designed to implement UN Agenda 21; note that that is the actual name - it refers to the UN's plans for the 21st century and seeks to begin controlling land use, concentrations of populations, and all that springs from a major Socialist plan to eliminate freedom and any real private ownership of land.
The Obamian move seems to seek to allow State, County, and Local governments to, in a step-by-step fashion, slowly implement the UN's plan starting with zoning changes. I will note that the first Bush singed on to Agenda 21 in 1992, followed by Billy shortly after.
The language used in the order is indeed frightening; note the quote below:
"Section 1. Policy. Sixteen percent of the American population lives in rural counties. Strong, sustainable rural communities are essential to winning the future and ensuring American competitiveness in the years ahead. These communities supply our food, fiber, and energy, safeguard our natural resources, and are essential in the development of science and innovation. Though rural communities face numerous challenges, they also present enormous economic potential. The Federal Government has an important role to play in order to expand access to the capital necessary for economic growth, promote innovation, improve access to health care and education, and expand outdoor recreational activities on public lands."
This is the cloak for for plan - redefine the land as being as asset that must be regulated for the benefit of all. After that they will be free to regulate or seize it until smallholders are gone and the bulk of the population will be under their control inside the cities, will have been disarmed, and will have no choice but to keep voting for those who will provide them with cheap or free housing and food.
I have always been reluctant to support any thought of nullification or secession. The Southern States wrongfully did so before anything had been done by the Federal Government that would prohibit their atrocious slavery and that was clearly wrong - you can't nullify or secede if nothing has been done with which you disagree. In other words, you must not consider nullification or secession for something that might happen. We are not facing the same circumstances today - we are being hit from all angles.
Here are more links. They can do the job of explaining this much better than can I:
http://www.americanthinker.com/2009/10/un_agenda_21_coming_to_a_neigh.html (Probably the most thorough)