Liberal Leader Justin Trudeau says the Conservative government's lack of environmental stewardship is what is preventing U.S. President Barack Obama from approving the Keystone XL pipeline.

Speaking from the Liberal convention in Montreal, Trudeau said neither Americans nor Canadians are convinced that the environment is a priority when it comes to the $7-billion pipeline.

"This government has done such a terrible job of living up to any sort of environmental responsibilities that it has had an impact on our trading partners," Trudeau told CTV's Question Period.

"President Obama's difficulty in approving infrastructure projects like the Keystone XL pipeline comes from the fact that we haven't given the Americans the cover to be able to say to their citizens, and even by extension our citizens, that the environment will be cared for."

During his keynote address on Saturday, Trudeau said the government must get the country's resources to global markets in an environmentally responsible manner.

Trudeau told Question Period that one of his priorities is to marry economic growth and environmental stewardship.

"Right now this government has done such a poor job on that there is a low degree of faith, and that's something we have to turn around," he said.

U.S. strategists who helped deliver Obama’s presidential victories in 2008 and 2012 attended the weekend convention, including Lawrence Summers, a former economic advisor to both the Clinton and Obama administrations, and Jennifer O'Mally Dillon, Obama's deputy campaign manager.

When asked what he thought of the support from the U.S. Democratic Party, and what it says about Harper's relationship with the U.S. president, Trudeau replied: "You'll have to ask Mr. Harper about that.

"I'm just pleased that we can draw on some of the expertise from people around the world about how to better connect with Canadians and on how to make people feel engaged in the political process."

O'Mally Dillon said there are a number of similarities in the leadership styles of Trudeau and Obama.

"At the core, a strong party is driven by a strong leader as much as anything else," she said from the Liberal convention.

While the Conservatives and NDPs have painted Trudeau as someone who lacks political experience, O'Mally Dillon pointed out that he's drawn new blood into the Liberal team.

"He's bringing new people into the process, he has strong family values and someone I think has a lot of strong ideas," she said. “I think the campaign and the party needs to highlight its focus on amplifying all that he is doing."