hundreds of protesters tried to disrupt the conference. >> lehrer: we'll get the latest from ray suarez at the summit. >> suarez: another day of negotiations here have still failed to produce a text world leaders can embrace here, but the u.n. secretary general told the "newshour," he still believes agreement is possible. i'll have a report. >> brown: there were some steps forward today, including pledges to protect rainforests. we'll see how that could play out in the amazon. >> lehrer: then, a performance review for federal reserve chairman ben bernanke. economist james galbraith and former fed vice chair alice rivlin debate his record. >> brown: and the relevance in our time of john maynard keynes: "newshour" economics correspondent paul solman has a somewhat off-beat explanation. ♪ my general theory made quite an impression i transformed the econ profession, you know me, modesty say it loud and say it clear, we're all keynesians now. >> lehrer: that's all ahead on tonight's "pbs...