NDP Leader Jack Layton was in Washington on Monday to press for changes to the North American Free Trade Agreement.

Layton spoke at the 'Take Back America 2008' conference, a gathering of grassroots and netroots activists, elected officials, business owners and policy experts of the progressive movement.

He said on CTV Newsnet's Mike Duffy Live that his calls for changes to NAFTA, particularly for new labour and environmental standards, were well-received.

"My message was 'let's work together and make trade deals that are sustainable and fair,'" Layton said.

Layton sees an opportunity to re-open the trade agreement after U.S. Democratic presidential hopefuls Hillary Clinton and Barack Obama made calls that they wanted changes for NAFTA.

And Layton seemed confident that either Obama or Clinton would be the next U.S. president that Canada would be dealing with.

"It's very exciting . . . (the movement) surrounding the candidacies of Senators Clinton and Obama," Layton said. "A real sense that a change in direction is in the offing in the United States."

"And that extends to the need to address some of these trade issues which are leaving working families and the increasing squeezed middle classes of the United States and Canada feeling more and more concerned."

Earlier this month, Layton sent both Clinton and Obama a letter warmly welcoming the positions of both candidates to "rethink NAFTA."

"Together, we can prudently lay the groundwork to craft trade agreements which will lead to improvements for the vast majority who have been left behind since NAFTA came into effect in 1994," Layton said in both letters.

"The Democrats in the U.S. can count New Democrats in Canada as allies in the vital effort to improve upon NAFTA and help build a modern 21st century North American economy that is prosperous, fair, and sustainable for today's families and future generations."

Layton said that he hoped NAFTA could be reworked to put labour and environment standards at the centre of the agreement. He said by doing so, it would boost many Canadians who have had to take second and third jobs to support their families.

Rainbow PUSH Coalition President Jesse Jackson also addressed the Take Back America 2008 conference.

"There must be a commitment to enforce the labour and the environmental dimensions of NAFTA for NAFTA to have any real chance of working as it was promised to work," Jackson told CTV Newsnet on Monday.