The US Department of Defense recently promulgated a new "defense" guidance document: "Sustaining US Global Leadership: Priorities for 21st Century Defense." I use scare quotes because it just doesn’t seem quite right to use "defense" to describe a document that — like its predecessors — envisions something like an American Thousand-Year Reich.
The greatest shift in emphasis is in the section "Project power despite Anti-Access/Area Denial Challenges." The "threat" to be countered is that China and Iran "will continue to pursue asymmetric means to counter our power projection capabilities."
That refers to a long-standing phenomenon: What Pentagon analysts call "Assassin’s Mace" weapons – cheap, agile weapons that render expensive, high-tech, weapons systems ineffective at a cost several orders of magnitude cheaper than the Pentagon’s gold-plated turds. In the context of "area denial," they include cheap anti-ship mines, surface-to-air missiles, and anti-ship missiles like the Sunburn (which some believe could destroy or severely damage aircraft carriers).