Two dozen Senate Republicans are warning President Obama not to link “wholly unrelated” climate change policies to approval of the proposed Keystone XL oil sands pipeline.

“You should approve the Keystone XL pipeline project on its merits alone without suddenly moving the goalposts after more than four years of review by tethering its fate to wholly unrelated and economically disastrous new regulatory policies,” states the new letter to Obama led by Sens. John Barrasso (R-Wyo.) and John Hoeven (R-N.D.).

Rumors have long swirled that if Obama approves Keystone, he might link approval to policies aimed at curbing greenhouse gas emissions, such as carbon standards for the nation’s existing power plants.

{mosads}Sen. Sheldon Whitehouse (D-R.I.), who opposes Keystone, told reporters in April that if Obama green-lights the pipeline, he should combine the action with other climate policy steps — comments that the Republicans flagged in their new letter.

“If they are determined to go down that path, and they can’t be dissuaded, then the important thing is to make sure that they surround that decision … [with] a whole formidable array of environmental and anti-carbon measures that can not just offset the harm that they do by approving [Keystone] … but actually turn the whole package into a very strong, anti-carbon pollution suite of strategies,” Whitehouse said.

The Obama administration is reviewing whether to issue a permit for TransCanada Corp.’s proposed pipeline, which would bring oil from Alberta’s oil sands projects across the border en route to Gulf Coast refineries.

Republicans who signed the letter — a group that includes Senate Minority Leader Mitch McConnell (R-Ky.) and the rest of the Senate GOP leadership team — say the Keystone decision should proceed on its own.

“We strongly urge you not to expand the scope of your review to include, or otherwise combine approval of the Keystone XL pipeline project with, expanded regulations or taxes that threaten use of America’s affordable, reliable, abundant coal, oil and natural gas resources,” the letter states.