As the clock ticks down to next month’s Copenhagen climate conference, environmental activists have their eyes on key world leaders whose decisions on whether to attend the conference could make or break the prospects for a binding international treaty. This week, two of those leaders have provided insights into their intentions. In a speech to the German parliament yesterday, Chancellor Angela Merkel said the United States, India, and China must outline their negotiating positions if she is to go to Copenhagen. “The European Union has developed clear and unambiguous negotiating positions,” Merkel told the Bundestag. “We now want contributions from the U.S. and from countries like China and India. … I will make a special personal effort to achieve this. And of course if it is successful, yes, I will go to Copenhagen.” American President Barack Obama likewise set conditions for his attendance at Copenhagen, telling Reuters on Monday that he would attend if his presence could help clinch an international deal. “If I am confident that all of the countries involved are bargaining in good faith and we are on the brink of a meaningful agreement and my presence in Copenhagen will make a difference in tipping us over edge then certainly that’s something that I will do,” he said. The presence of leaders like Obama and Merkel could make all the difference in the delicate climate negotiations. Their attendance would lend weight to their countries’ negotiating stances, while their absence would be seen as a sign that Germany and the United States lack confidence in the ability of the international community to coordinate effective climate action. Keya Chatterjee, the U.S. acting director of the climate program at the World Wildlife Fund, considers Obama’s decision particularly important. “The whole world is being asked to trust the U.S., but the global community can’t take it seriously if Obama isn’t there,” she told Time. Other top Western leaders, including the UK’s Gordon Brown and France’s Nicolas Sarkozy, have already pledged to attend the conference.