In the first decade of the twenty-first century, diplomacy came to be widely debated not only by practitioners, policy experts, and academics but also in the popular press and among the general public. One of the most significant debates concerned whether diplomacy had been or would be successful in preventing the Iraqi government of Saddam Hussein from possessing (or continuing to possess) weapons of mass destruction. Between 2001 and 2003, it appeared that most of the global public who were in a position to read a newspaper, watch television, or surf the Internet had formed an opinion, irrespective of whether they knew who was involved or how the diplomacy in question was being conducted. The US government of President George W. Bush and US allies, including the United Kingdom and Italy, were criticized by numerous other governments and civil society organizations for deciding on their own that multilateral diplomacy under the aegis of the United Nations (UN) had failed and hence to take military action against Iraq.
This debate about diplomacy raises a number of questions that point to underlying, scholarly debates about contemporary diplomacy that have significant implications for how it will be practiced in the future. The first question is a definitional issue with epistemological underpinnings: What is to count as diplomacy, and what is not? That these questions are fundamental to the study of diplomacy shows that the longstanding consensus about “what we mean by diplomacy” is now breaking down. The second, overlapping debate is about the extent to which diplomacy in the contemporary period has changed and is different from, or similar to, diplomacy in the past. Key to unpacking this debate is an understanding of what constitutes continuity and change. The third debate concerns the role of theory in diplomacy: What is the relationship between theorizing and practicing diplomacy? The most intellectually challenging of the three debates, it perhaps has the most far-reaching implications for how we understand and engage in diplomacy in the contemporary environment.
That these questions engender debate rather than consensus is a result of different sorts of knowledge and understanding being apposite to different issues. Some issues have emerged because of new empirical information that challenges previously held understandings. Others have arisen as a result of competing modes of analysis of information. Yet others, such as the theory and practice debate, arise when more radically different and incompatible theoretical and epistemological approaches come into contention.

PIGMAN, Geoffrey Allen. Debates about Contemporary and Future Diplomacy. In: KERR, Pauline; WISEMAN, Geoffrey. Diplomacy in a Globalizing World. Theories and Practices. New York/Oxford: Oxford University Press, 2018, p. 72–89. (adapted)