U.S. Ambassador to Canada David Jacobson says a letter from Saskatchewan Premier Brad Wall urging the White House to approve the Keystone XL pipeline will have little impact on the project鈥檚 outcome.

The letter, also signed by 10 Republican governors, says the pipeline is fundamentally important to the economic prosperity of both the United States and Canada.

When Jacobson was asked if it would have an impact on U.S. President Barack Obama鈥檚 decision, he replied: 鈥淣o, I really don鈥檛.鈥�

Jacobson told CTV鈥檚 Question Period that a science-based analysis will determined whether the proposed $7-billion TransCanada pipeline will get Obama鈥檚 stamp of approval.

鈥淲hat鈥檚 going on here and what鈥檚 going to determine this is how do we strike the right balance between our need for safe and secure sources of energy 鈥� Canada -- and our concerns about the environment,鈥� Jacobson said.

鈥淭hese are the same issues that people in Canada are wrestling with and that鈥檚 what this process is all about, and hopefully we鈥檙e getting toward the end of it.鈥�

If the project is approved it would carry oil 3,460-kilometres from Alberta to Steel City, Nebraska, and then on to refineries on the Gulf Coast.

Last year, Obama reversed his decision on the controversial project until after the election. As Obama鈥檚 second-term inauguration approaches, TransCanada says it intends to re-apply for the presidential permit needed to cross the border, and expects the White House to approve the application in the first quarter of 2013.

Jacobson said it鈥檚 difficult to strike a balance between the economic benefits of the pipeline, and the environmental impact. He added that Americans remain divided on the issue.

The project was rejected last year to re-evaluate the pipeline鈥檚 route, which cuts through the ecologically-sensitive Sand Hills area in Nebraska. A newly-proposed route avoids the Sand Hills region.

鈥淭he Governor of Nebraska and the environmental group in Nebraska that was evaluating this came up with what they believe is a better route,鈥� said Jacobson. It鈥檚 now up to the State Department, and we鈥檒l see what happens.鈥�