Preventing the Keystone XL pipeline has become a rallying point for the environmental movement, which has won over President Obama who has said he will veto efforts by Congress to force an approval.

However, one pol who has been curiously silent on the issue is presumptive 2016 Democratic contender Hillary Clinton.

A look at many of the major donors to the Clinton Foundation may just offer an explanation. From CommonDreams:

According to a voluntary disclosure from the Foundation, in 2014 the not-for-profit received between $250,000 and $500,000 from Canada's Foreign Affairs, Trade, and Development department, which has pressed for approval of the Keystone XL pipeline. The agency's own website states that one of its priorities is to "Deepen commercial relations with the United States through support for innovation and foreign investment and promote Canada as a stable and secure source of energy and energy technology, such as the Keystone XL initiative." This Canadian agency is not the only donor aligned with big oil. Numerous fossil fuel giants sent direct payments to the foundation in 2014, including Exxon Mobil Corp., which donated up to $5 million, Anadarko Petroleum Corp., BP, ConocoPhillips Co., Chesapeake Energy Corp., Citgo Petroleum Corp. and Occidental Petroleum Corp, the Hill reported. Big Oil has played a key role in lobbying in favor of the Keystone XL pipeline, including in a letter to U.S. President Barack Obama signed by the CEOs of ExxonMobil and Anadarko.

When asked about the pipeline this past summer by a Canadian newspaper, Clinton replied, “I can't respond. She continued, “I can’t really comment at great length because I had responsibility for it and it’s been passed on and it wouldn’t be appropriate, but I hope that Canadians appreciate that the United States government — the Obama administration — is trying to get it right. And getting it right doesn’t mean you will agree or disagree with the decision but that it will be one based on the best available evidence and all of the complex local, state, federal, interlocking laws and concerns.”