Canny U.S. diplomacy, or barely redeemed gaffe? Russian opportunism, or sincere effort to stave off war? Syrian feint, or desperate gambit by a regime running scared? Whatever one thinks about how the U.S. and Russia reached their agreement to destroy Syria's chemical weapons arsenal, one thing is clear: It couldn't have been achieved in the absence of a strong international consensus against the use of chemical weapons.

Strengthening the ability of the United Nations to identify and enforce the world's collective will should be high on President Barack Obama's foreign policy agenda, beginning with his trip tomorrow to the UN General Assembly.

Widespread support for the Chemical Weapons Convention gave the U.S. a rallying point for its effort to hold Syrian President Bashar al-Assad accountable for brutalizing his people. It also gave Syria and its patron Russia a face-saving way to avert a U.S. strike: They weren't knuckling to pressure; Syria was merely signing a treaty that almost all of the world's nations had already joined. On paper, at least, that outcome is exactly the kind of result hoped for by champions of collective security.

For the U.S., this peacekeeping impulse can reduce the need to spend diplomatic capital or deploy military might. Yet two obstacles make the UN less effective than it could be: first, a creaky Security Council that has become paralyzed by division; and second, the U.S. tendency to punt on treaties or to exempt itself from provisions it doesn't like.

The fight over the text of a Security Council resolution on the enforcement of the Syria agreement is the latest evidence of the stalemate among its five permanent members. Since 2011, Russia and China have vetoed three resolutions on Syria, with Russia also preventing a vote on resolutions condemning chemical attacks and calling for humanitarian relief efforts.

Granting the permanent members a veto was the price of getting them to endorse collective security in 1945. Yet Security Council membership now represents a much smaller slice of the world's population and leaves out big economic players such as Japan and Germany (the second and third biggest UN funders) as well as emerging powers India and Brazil. Even by the council's most important criterion -- the ability to safeguard international peace -- the current membership comes up wanting.

How to expand the council is one of the most critical challenges facing the United Nations. You won't find any mention of it, however, in Obama's four previous speeches to the annual General Assembly. The U.S. should be leading the campaign to build consensus on the process for admitting new members, what the mix of permanent and elected members should be, and what powers they should have.

David Fuller's view A healthy global economy, in which we all have interests, includes a process of transformation from a unipolar to a multipolar world. This is already occurring and it could make the world safer by reducing serious international friction. However, this might not happen because the current structure of the United Nations Security Council is too limited for today's world. Specifically, the Security Council is too small and insufficiently representative of the world's increasing population within developing economies.

The United Nations Security Council currently has five permanent members - China, France, Russia, the United Kingdom and the United States. Each has a veto which can block any proposal by other members. Clearly, this is far too much power for any single country in today's world. The Security Council would be far more representative if it was at least doubled in size. Additionally, the single country veto power should be scrapped and replaced by a majority vote of perhaps 60 percent.

This would give the United Nations more representative authority and influence. The Security Council would be more effective. It could even help to prevent a serious military conflict among superpowers which have weapons of unconscionable power.