TransCanada is demanding that the U.S. fork over $15 billion to make up for the fact that the company didn’t get to build the Keystone XL pipeline. That’s one damned expensive temper tantrum.

On Friday, TransCanada filed a formal request under NAFTA seeking to recover costs and damages related to the thwarted pipeline project, following through on a threat it made in January. The Canadian firm claims that the Obama administration’s decision to reject the pipeline was unjustified and violated the U.S.’s obligations under NAFTA. “[T]he rejection was symbolic and based merely on the desire to make the U.S. appear strong on climate change,” TransCanada complained in its filing.

Climate activists and other environmentalists say this is a perfect example of why they oppose many trade deals, like the Trans-Pacific Partnership (TPP), which Obama is currently trying to get approved. “The TPP would empower thousands of new firms operating in the U.S, including major polluters, to follow in TransCanada’s footsteps and undermine our critical climate safeguards in private trade tribunals,” said Michael Brune, executive director of the Sierra Club.

The State Department argues that the Keystone rejection was consistent with NAFTA requirements, but some trade experts say there’s a real chance TransCanada could win its case.

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