Since no ultimate international authority is in place to enforce the will of the majority of the world's seven billion people, international politics is largely about the capacities and relative powers of the individual states that constitute the global system. Conflict between and among states emerges when interests are challenged and states respond by exercising power in bargaining situations or, occasionally, by threatening or engaging in military confrontation. The search for security is never ending. A writer of the Roman Empire, Vegetius, once recommended, si vis pacem para bellum, “if you desire peace, prepare for war.” In fact, it might be said that states prepare for conflict more than they do for peace and harmony. It is unfortunate that governments often misuse the concept of war for rhetorical purposes – as when they speak of a war on drugs, poverty, or terrorists – a practice that does little to illuminate the nature of war.

This chapter builds on the concepts of old and new security dilemmas to discuss what happens when security fails. Violent state conflicts are frequent, and come in many types, but here we focus primarily on those between and among states. There are many questions to answer, perhaps the most basic of which are the following: What causes war? Can it be prevented or is it inevitable? We use the three levels of analysis discussed in Chapter 3 to determine whether they can advance our understanding of what causes war.

We have examined global interactions in terms of history, politics, economics, conflicts, and human rights. Beyond these vital topics, and arguably just as significant globally, are the environment we all share, patterns of population growth and aging, and diseases and health issues that know no borders. Clean air, water, and fertile land for growing food are basic requirements for healthy and vibrant life, but there is a growing mismatch between fulfilling these escalating needs of the world's burgeoning population and our methods of achieving economic progress.

This chapter examines areas in which there are pressing threats to our shared globe: the environment, demographic change, and health. Our first topic, the environment, is extremely complex (Box 15.1). Climate change in particular has become a serious and controversial issue. Energy supply is critical for the global economy, but greenhouse gases emitted from fossil fuels and ozone-depleting chemicals contribute significantly to global warming and atmospheric degradation. We examine these perplexing environmental and energy issues as two sides of the same coin. We then consider alternative energy sources and other important environmental issues including water, agriculture, and biodiversity that also have global impacts.

Demographic issues underlie and interact with environmental problems today, so our second topic is population trends. Uneven population growth and distribution combined with factors such as aging and international migration have significant implications for the global environment, economic progress, and security. The third and final section of the chapter focuses on world health issues – topics including child and maternal health, contagious diseases, HIV/AIDS, and pandemics. Increasingly, global health is being viewed as an economic development issue and also as a human rights and security issue.

While there is no international authority that can impose laws on people around the globe and force them to be obedient, there is a new kind of global governance in flux. States accept some forms of international law, sign treaties, and even join various international organizations for their mutual benefit or to approve certain norms of behavior, yet none subjects itself to a higher set of decision makers or laws than those of its own domestic authorities. This is illustrated by the fact that international institutions cannot back up their rules, demands, or threats unless member states stand behind them. They do not have courts, police, prisons, or soldiers to enforce their rulings unless states supply them. Simply put, the global community lacks the sinews of sovereignty.

International law and intergovernmental institutions are intermittently on the minds and in the emotions of informed citizens around the world, because the media carry information about them on a regular basis. Political leaders try to win the support of these international authorities in economic and security matters as they negotiate new treaties, participate in global institutions, and contribute to the evolution of new norms, rules, and practices. Yet the details about how such topics and events are handled or mishandled in international forums are neither covered well by news organizations nor followed closely by the public. Think of events such as the wars in Afghanistan and Iraq, military intervention in Libya, violent upheaval in Syria, the war-crime trials in The Hague, prisoners of war held in Guantánamo Bay, torture and humiliation in Iraq's Abu Ghraib prison, and genocide in Darfur and Rwanda. All of these topics raise issues about international laws concerning war, murder, and torture that are complex and only vaguely understood except by specialists.

Part IV introduces the international aspects of economics, explaining its importance in the global sphere and relating it to questions of development, prosperity, poverty, and hunger.

Chapter 12 outlines traditional and scholarly concepts and theories in the field and assesses the contemporary importance of liberal internationalism, economic nationalism, neo-Marxism, and the rise of state capitalism. The prospects for global economic governance are controversial, and they are evaluated in terms of the benefits and criticisms of organizations such as the World Bank, the International Monetary Fund, and the World Trade Organization. The current global economic downturn and issues of government debt and financial reform provide a sense of urgency to these global economic issues.

Chapter 13 deals with global inequalities. It assesses winners and losers among states and peoples in the global economy and discusses issues of poverty and hunger, how they are being addressed by the UN Millennium Development Goals, and what progress is being made. On the basis of income earned per day, more than one of every four people on Earth lives in extreme poverty. The overall gap between rich and poor continues to grow, with 1.4 billion people now living below the global poverty line of US $1.25 per day. Forty-two million people are currently displaced by conflict or persecution.

The two previous chapters focus on two major types of actors on the global stage – states and intergovernmental institutions. But these are not now, and never have been, the only players. There are others vying for attention – actors that are not confined by states and that often challenge states rather than support them. In this chapter, therefore, we move beyond states and their institutional creations, such as the United Nations and the European Union, to examine other significant nonstate participants in global politics.

Around the world today people are mobilizing across state borders to bring about political and social change, pressuring governments to help change social norms. They are forging new connections and organizing new institutions with novel interests. These are transnational actors, sometimes known as transnational advocacy groups (TANs), and their activities across state borders are known as transnational relations. TANs try to exert new pressure on states to alter their interests and change social norms. To do this, they produce new knowledge about issues, frame issues to mobilize popular support, or provide social pressure for policy change. They facilitate cooperation among states by providing information about international agreements and monitoring compliance. Their effectiveness is influenced by domestic political institutions, and they can mobilize social pressures more effectively in democracies than in autocracies. Transnational actors include both legal and illegal institutions that are involved in many types of behavior. Who are they, and what do they do?

The world faces many threats to human security and prosperity in the 21st century. Many of them are from people; others are products of the economic and physical environment. Recently, the U.S. Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism produced a slim, powerful volume on future world risks. It concluded that we know the threats we face, we know that our margin of safety is shrinking, and we also know what must be done to counter the risks. With similar concern, the Secretary-General of the United Nations, Ban Ki-moon, declared that rising temperatures due to climate change would “increase pressure on water, food, and land; reverse years of development gains; exacerbate poverty; destabilize fragile states; and topple governments.”

This book describes and explains the factors behind these and other global issues and invites readers to consider whether the conclusions and warnings of the U.S. president's advisors and the leader of the world organization were well founded. It challenges readers to study, understand, and evaluate power and responsibility in global politics. The most serious threats today include the proliferation of weapons of mass destruction, worldwide terrorist networks, the tenuous end to the wars in Afghanistan and Iraq, armed conflict in the Middle East and North and Central Africa, world financial crises, global climate change, global reliance on oil, global poverty, global infectious diseases, and the rising power of hostile actors on the world stage. These and other issues are, or should be, of deep concern to everyone in all parts of our evermore connected world.

The three chapters that comprise Part I of this book outline important fundamentals for the study of contemporary global politics. They take a pragmatic approach, highlighting the complexities of the subject and recognizing the contributions of historians and modern theorists. They show the need for a question-driven approach by stressing the significance of history and theory to an understanding of how our disordered world works.

Chapter 1 discusses three significant topics that profoundly influence the patterns of world politics today: the perpetual quest for security, the march of globalization, and the complex role of states and identities. Together they help us understand the continuities and changes in global politics.

Chapter 2 shows that the study of global politics requires an understanding of history that is not limited to Europe and North America. It traces the rise and fall of the world’s extended empires and great powers from the earliest recorded history to the end of the Cold War. For many centuries it was not clear whether Asia, Europe, or the Middle East would dominate the world. The rise of the modern state and the economic progress that followed the industrial revolution tipped the scale in favor of Europe and, later, the United States. The chapter traces the historical patterns of interaction of the world’s great powers over time, concluding with the six areas that dominate global politics today: the United States, China, Japan, India, Russia, and the European Union. In Part II we focus on these great powers today and ask whether the balance of power is about to shift again.

The five chapters of Part II outline the role and the relative powers of states, their leaders, and their challengers in international affairs, providing an overview of the numerous actors in global politics.

The first two chapters describe political authority and global power, placing the six major powers – the United States, China, Russia, India, Japan, and the European Union – in the context of contemporary international debates and controversies. Chapter 4 assesses all states and their leaders in terms of their power, capabilities, and decision-making processes. Chapter 5 maps the shifting distribution of state power and influence in the modern world, particularly among the six major powers. Chapters 4 and 5 both confront the issues of comparative advantage and international action.

Chapter 6 focuses on important aspects of global governance in our interdependent but disordered world – the growth and role of international law and supranational courts, institutions such as the United Nations and the European Union, and functions such as peacekeeping and peace enforcement. Together with other institutions such as the International Criminal Court, these institutions create a landscape of creeping global governance that affects state sovereignty and people everywhere. Realists may downplay the importance of such institutions, and liberals may conclude that these institutions are desirable but not perfect, but both recognize them as increasingly significant and resilient.

The Standard Model of particle physics

Particle physics is at the heart of our understanding of the laws of nature. It is concerned with the fundamental constituents of the Universe, the elementary particles, and the interactions between them, the forces. Our current understanding is embodied in the Standard Model of particle physics, which provides a unified picture where the forces between particles are themselves described by the exchange of particles. Remarkably, the Standard Model provides a successful description of all current experimental data and represents one of the triumphs of modern physics.

The fundamental particles

In general, physics aims to provide an effective mathematical description of a physical system, appropriate to the energy scale being considered. The world around us appears to be formed from just a few different particles. Atoms are the bound states of negatively charged electrons (e−) which orbit around a central nucleus composed of positively charged protons (p) and electrically neutral neutrons (n). The electrons are bound to the nucleus by the electrostatic attraction between opposite charges, which is the low-energy manifestation of the fundamental theory of electromagnetism, namely Quantum Electrodynamics (QED).

The Standard Model

The ultimate theory of particle physics might consist of a (simple) equation with relatively few free parameters, from which everything else followed. Whilst the Standard Model (SM) is undoubtedly one of the great triumphs of modern physics, it is not this ultimate theory. It is a model constructed from a number of beautiful and profound theoretical ideas put together in a somewhat ad hoc fashion in order to reproduce the experimental data. The essential ingredients of the Standard Model, indicated in Figure 18.1, are: the Dirac equation of relativistic quantum mechanics that describes the dynamics of the fermions; Quantum Field Theory that provides a fundamental description of the particles and their interactions; the local gauge principle that determines the exact nature of these interactions; the Higgs mechanism of electroweak symmetry breaking that generates particle masses; and the wide-reaching body of experimental results that guide the way in which the Standard Model is constructed. The recent precision tests of the Standard Model and the discovery of the Higgs boson have firmly established the validity of the Standard Model at energies up to the electroweak scale. Despite this success, there are many unanswered questions.

Probing the structure of the proton

Electron–proton scattering provides a powerful tool for probing the structure of the proton. At low energies, the dominant process is elastic scattering where the proton remains intact. Elastic scattering is described by the coherent interaction of a virtual photon with the proton as a whole, and thus provides a probe of the global properties of the proton, such as its charge radius. At high energies, the dominant process is deep inelastic scattering, where the proton breaks up. Here the underlying process is the elastic scattering of the electron from one of the quarks within the proton. Consequently, deep inelastic scattering provides a probe of the momentum distribution of the quarks.

The precise nature of the e−p → e−p scattering process depends on the wavelength of the virtual photon in comparison to the radius of the proton.