In a letter to the Senate dated February 24th President Barack Obama used his power of veto on the proposed pipeline:
I am returning herewith without my approval S. 1, the “Keystone XL Pipeline Approval Act.” Through this bill, the United States Congress attempts to circumvent longstanding and proven processes for determining whether or not building and operating a cross-border pipeline serves the national interest.
The Presidential power to veto legislation is one I take seriously. But I also take seriously my responsibility to the American people. And because this act of Congress conflicts with the established executive branch procedures and cuts short thorough consideration of issues that could bear on our national interest — including our security, safety and environment – it has earned my veto.
– Barack Obama
The matter has been returned to Congress to continue to debate the issue.