The 81st session of the United Nations General Assembly is taking place in New York at a time when international diplomacy is increasingly divided between broad multilateral negotiations and direct engagement among the world’s most powerful states.

The contrast is particularly visible on September 24, as governments and diplomats continue high-level discussions at the United Nations while U.S. President Donald Trump and Chinese President Xi Jinping hold their own high-level bilateral meeting in Washington. Reuters described the situation as a “split-screen” moment for global diplomacy.

The UN’s Multilateral Role

The United Nations brings together all 193 member states. During the current high-level week, governments are discussing conflicts, international security, climate change, development, emerging technologies and other global challenges.

The official UN schedule places the General Debate from September 22 through September 26 and September 28, with additional high-level meetings covering issues including sea-level rise and pandemic preparedness.

The central idea behind this system is that major international problems can be discussed collectively rather than being determined only by the most powerful countries.

However, the UN’s ability to produce concrete outcomes can be affected by disagreements among major powers, particularly in the Security Council, where five permanent members possess veto power.

Why Bilateral Diplomacy Still Matters

At the same time, major powers frequently use direct negotiations to address issues that are difficult to resolve through larger international forums.

The Trump-Xi meeting illustrates this approach. Their discussions include trade, artificial intelligence, defense and other strategic issues. The two countries have extensive economic ties but also significant disagreements over technology, security and Taiwan.

Bilateral meetings can allow leaders to negotiate directly and privately on specific issues. But agreements reached between two powerful countries do not automatically represent the interests or positions of all other governments.

Wars Are Testing Multilateral Diplomacy

The current UN session is taking place against the backdrop of wars and prolonged international crises.

The UN has placed conflicts and international security among the major issues for the high-level week. Secretary-General António Guterres has called for de-escalation and dialogue while warning that international law and the UN Charter are under significant pressure.

Ukraine, the Middle East and humanitarian crises are therefore not simply regional questions. They also test whether countries can agree on common principles and collective responses.

AI Adds a New Dimension

Artificial intelligence has become another important part of international diplomacy.

The technology has economic, military and security implications, while governments are also considering questions surrounding AI safety and international governance.

The United States and China are simultaneously competing technologically and exploring ways to manage certain shared AI risks. The issue demonstrates how modern geopolitics increasingly connects technology policy with traditional security and economic diplomacy.

The Central Question: Collective or Great-Power Diplomacy?

The current diplomatic landscape does not necessarily represent a simple choice between the UN and bilateral negotiations.

Both systems operate simultaneously.

The UN provides a forum where all member states can present their positions and negotiate collectively. Bilateral diplomacy allows major powers to address disputes directly. Regional organizations, smaller groups of countries and informal diplomatic channels add further layers to the international system.

The challenge arises when these channels produce conflicting priorities or when major-power disagreements prevent collective institutions from taking effective action.

What to Watch

Several developments during and after the current UN General Assembly could indicate how international diplomacy is evolving:

• Whether governments can reach common positions on ongoing conflicts.
• Whether major powers support stronger international mechanisms for emerging technologies.
• How the UN responds to disagreements among permanent Security Council members.
• Whether bilateral agreements between major powers complement or bypass wider multilateral negotiations.
• How governments address climate, humanitarian and development challenges alongside security concerns.

The 2026 General Assembly therefore offers a snapshot of a changing international system. The United Nations remains the world’s broadest diplomatic forum, while direct negotiations between major powers continue to play an important role.

The key geopolitical issue is how these different forms of diplomacy can operate together when countries have sharply different interests.