The ratification of the nuclear arms treaty with Russia is literally just a start. President Obama has mapped out further steps to limit nuclear weapons, all in entirely new territory. Both the U.S. and Russia have thousands of additional nuclear weapons in categories that have never been subject to limits -- tactical nuclear weapons, non-deployed warheads that could be used in a crisis. Then there are the other nations that possess nuclear weapons, such as China, France and Britain, which have never been subject to arms control negotiations. These are just a few of the thorny issues that the Obama administration would like to see included in new arms control talks.