Paul Krugman: Is the threat of speculation a reason to shun cap and trade?

There are many obstacles to taking action on climate change. Most of those obstacles have deep roots: there are powerful interest groups that don’t want market prices to reflect true costs, and there are ideologues — financially supported by these interest groups — who don’t want to admit that sometimes the government has to intervene.

But there’s also, it seems, growing opposition to cap-and-trade from people who should be on the side of progress — but whose reaction is basically “Eek! Markets!Wall Street! Speculation! Bad!”