In 1937, Adolph Hitler violated the Versailles Treaty by sending the Wehrmacht to occupy the Rhineland. The Rhineland was a part of Germany, but the treaty forbade stationing troops there. In 1939, Adolph Hitler broke the Munich agreement by occupying the second half of Czechoslovakia. In both cases, Hitler gambled that Neither France nor Britain would respond militarily. He was correct both times.
The Hutu in Rwanda propagandized and plotted for years in preparation for their genocide of the Tutsi in 1994. The UN had stationed "Peace Keepers" in Rwanda to prevent violence and renewal of war between the two groups. The Hutu gambled that they could amass their weapons and forces in the open and intimidate the UN forces into inaction. They were so right in their gamble that the UN forces even surrendered to the killers Tutsi people who had sought refuge.
For eleven years Saddam Hussein continually violated the truce agreement that ended the Persian Gulf War. He concealed his WMDs and WMD development programs. He developed missiles with ranges longer than were permitted. His forces fired SAMs at US and British planes that were trying to enforce the "No-Fly Zones" that were imposed by the truce agreement. His government repeatedly interfered with UN groups tasked with searching for WMDs. For eleven years, Saddam Hussein gambled that the US and the UK would not take serious action to stop him or remove him from power. Saddam was right throughout those eleven years.
Kim Jong Il managed to persuade the West, especially the US, to feed his people, supply him with the key materials and equipment for building nuclear weapons, and frustrate monitoring long enough to produce nuclear weapons. Now North Korea's capabilities are considered real and dangerous enough that the US and neighboring countries are now negotiating with him rather than taking decisive military action.
Iran's leaders are smart enough to learn from history. They know that Hitler's, the Hutu's, and Saddam's luck eventually ran out through over-reaching their abilities and the world's patience. However, they believe that through sending mixed messages of threats and assurances of peaceful intent that they can paralyze Europe and the US into inaction long enough to get their nuclear weapons constructed and deployed, forcing the US to forgo military action more or less permanently (or at least until, from the Iranian leaders' perspective, such intervention will no longer matter). Will the US pay off the Iranian leaders' gamble?
