GLOBAL TRADE talks have a rocky history. Riotous protests at the Seattle summit five years ago marked the birth of the anti-globalization movement, and although the special atmosphere after the terrorist attacks of 2001 made possible a successful meeting that year in Doha, Qatar, the 2003 summit in Cancun, Mexico, fell apart in acrimony. This record has raised questions about whether further global trade liberalization is possible. The new (and justified) assertiveness of developing-country negotiators, often advised by nongovernmental organizations impatient with compromise, has complicated the process of reaching consensus. And the entanglement of trade with other emotionally charged issues -- labor rights, the environment -- has made the negotiators' job more difficult still.

Set against that pessimism, last week's talks in Geneva were a great success. Negotiators from 147 countries did what they had failed to do in Cancun two years ago: They agreed on the broad principles that might govern another round of trade liberalization. The most significant achievement was to promise an end to subsidies for agricultural exports, which rich countries (particularly the European Union) use to compete unfairly with producers from poor ones -- though the date by which these export subsidies will be eliminated remains to be settled. Last week's deal also laid down principles for cutting agricultural production subsidies and tariffs, though the depth of the cuts has yet to be determined. It singled out cotton subsidies, which the United States doles out to the huge detriment of poor West African producers, as an area on which future negotiations must concentrate.

An agreement to carry on searching for agreement may not sound exciting. But the potential benefits of an eventual 147-country deal are substantial -- far bigger than the small bilateral and regional trade treaties that are the alternative. Trade increases prosperity by forcing companies and workers to compete internationally, and the wider and more open that competition, the greater the resulting efficiencies. Moreover, the agricultural focus of the current round of trade talks marks an improvement on previous rounds. It is a scandal that rich countries spend about $300 billion a year on farm subsidies, suffocating producers in poor countries hoping to export their way out of poverty.

President Bush's trade representative, Robert B. Zoellick, deserves credit for getting trade liberalization talks back on track, despite the political pressures of an election year marked on the Democratic side by disturbing protectionist rhetoric. Mr. Zoellick forged a close partnership with his European Union counterpart, Pascal Lamy, as well as with trade ministers from leading developing countries; his energetic multilateralism defies the stereotype of the Bush administration. But Mr. Bush's critics are not relenting. Thomas A. Daschle (S.D.), the Democratic leader in the Senate, complained that "big agribusiness has won and family farmers in South Dakota and across the country have lost," even though there is far too little detail in the agreement to support such a conclusion. Sen. John F. Kerry (D-Mass.), meanwhile, is silent on the issue. Voters may wonder whether, if he were to be elected president, Mr. Kerry would complete the job that has now been half-accomplished by the current administration.