WASHINGTON -- Expect to see more ads skewering Roy Blunt like that recent spot with the names of oil companies scrolling across the screen.

The League of Conservation Voters Action Fund, the political arm of the environmental movement, intends to keep its focus on Missouri's Senate race with independent expenditure ads and door-knocking across the state.

Tony Massaro, the LCV's senior vice president of political affairs, said today that Missouri will be his organization's top priority nationally in the coming weeks -- followed closely by contests for open Senate seats in Pennsylvania and New Hampshire.

Speaking in Washington today, Massaro said that the league's polling in July showed Blunt, a Republican, leading Robin Carnahan, the Democratic nominee, "at the error margin."

"We believe that it is a tight race," he said.

A Rasmussen Reports survey of 750 likely voters published this week showed Blunt ahead of Carnahan 51-40 percent. That poll was said to have an error margin of plus-or-minus 4 percent.

Massaro said his group's survey turned up a bit of a surprise: A plurality of voters endorsing climate change legislation in Congress.

Here's how the question was asked, followed by the results:

Here are some laws passed in at least one House of Congress in the past two years. Please tell me whether you approve or disapprove of each one:

The plan to encourage clean energy production known as cap-and-trade.

Approve: 45 percent. Disapprove 40 percent.

With voters mostly concerned most about the economy, Massaro said, a primary mission is persuading Missourians of the economic benefits of green technology  -- and in so doing influencing how they vote.

"Our challenge is to show people who see only a downward slope in the economy that there is a way up," he said.