It is ironic that some people seem to think the reason for the Second Amendment is to support our government in time of need. It is the exact opposite.
Thomas Jefferson, well known for his influence on the U.S. Constitution, has said, "The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government" (Thomas Jefferson Papers, page 334).
When tyrants take over a country, one of the first things they do is outlaw the private ownership of guns. Can't happen here? Look around at the changes that are taking place. Are the people wanting to outlaw guns in favor of small government or a larger, ever more encroaching, government?