The protest, in April, the first time that campaigners have openly carried weapons in a US national park, came amid growing fears in Washington - voiced last week by Bill Clinton - over the violent anti-Government rhetoric that is spreading across the American heartland.
Equally alarming to many is that the gathering was made up of little-known militia and gun-obsessed organisations that have begun to proliferate since Mr Obama came to power.
One reason for their growing numbers is that they believe the powerful and well-funded National Rifle Association, a powerhouse in expanding the right to bear arms over the past 30 years, has become too mainstream and is not taking on the Obama Administration aggressively enough.
