WASHINGTON – U.S. Senator Claire McCaskill has joined an effort by 11 Senators calling on President Obama to implement an explicit timeline for approval of the Keystone XL Pipeline permit.

Highlighting the repeated delays in the approval process over the last several years, the Senators urged the President to make a final decision no later than May 31, 2014.

McCaskill-a strong supporter of the Keystone Pipeline’s construction-was joined by Senators Heidi Heitkamp (N.D.), Mary Landrieu (La.), Mark Begich (Alaska), Mark Pryor (Ariz.), Joe Manchin (W.Va.), Joe Donnelly (Ind.), Mark Warner (Va.), Jon Tester (Mont.), John Walsh (Mont.), and Kay Hagan (N.C.).

“This process has been exhaustive in its time, breadth, and scope. It has already taken much longer than anyone can reasonably justify,” the Senators wrote. “We cannot miss another construction season, given the long cold winter this year along the Keystone XL route and the time required for ground thaw, we could be looking at a very short season. We need a definitive timeline laid out, a timeline that reduces the comment period for federal agencies, officials and other entities.”

Earlier this year, after the State Department completed its final environmental impact statement of the pipeline, McCaskill called on President Obama to approve the Keystone project. McCaskill previously urged then-Secretary of State Hillary Clinton to speed up the lengthy review process for the northern portion of the pipeline, citing the significant potential for jobs and increased energy security the pipeline’s construction would mean for the United States. McCaskill has long been a supporter of the swift approval and construction of the Keystone XL pipeline, previously voting to force approval of the project.