Mexican President Felipe Calderon shook hands with Secretary of State Hillary Clinton at Los Pinos Presidential Palace in Mexico City, Jan. 24, 2011. Saul Loeb/Agence France-Presse/Getty Images

Barack Obama and his former Secretary of State Hillary Clinton have been lauded by environmentalists for their opposition to the proposed Keystone XL pipeline and their climate-themed speeches demanding that the U.S. use its power to keep more fossil fuels in the ground. But both politicians have worked to expand fossil fuel development. A new deal with Mexico spotlights the gap between Obama's and Clinton's rhetoric and some of their actions.

In October the Obama administration approved the first fossil fuel export deal with Mexico’s state-run oil company. Only weeks earlier, the White House had threatened to veto the oil-industry-backed bill to lift larger petroleum export restrictions. The administration said Congress should instead “be focusing its efforts on supporting our transition to a low-carbon economy.”

But back in 2012, Obama and Clinton forged the so-called “U.S.-Mexico Transboundary Hydrocarbons Agreement,” designed to promote fossil fuel development. The state department said the pact would help energy corporations expand offshore drilling and “unlock areas for exploration and exploitation" in locations between the two countries. The agency said the deal will make “nearly 1.5 million acres of the Outer Continental Shelf more attractive” to energy companies.

Clinton said during the signing ceremony that the agreement “helps promote the safe, efficient, and equitable exploration and production” of fossil fuels. The deal was ratified by Congress in 2013.

Clinton’s support for offshore drilling as secretary of state mirrored her support for such endeavors while she was a senator. In the years before BP’s Deepwater Horizon disaster, Clinton cast key votes to expand offshore drilling in the Gulf of Mexico and against restrictions on drilling off the coast of Florida.

Clinton was endorsed this week by the League of Conservation Voters.