At the urging of President Donald Trump, the State Department has issued a presidential permit for TransCanada's Keystone XL, an important step forward for construction of the pipeline and a complete reversal of a decision made under former President Barack Obama.

The State Department permit, issued March 24, is necessary for the pipeline to cross the U.S.-Canadian border. The pipeline would transport more than 800,000 barrels of oil from Western Canada to Nebraska, then connect with an existing pipeline system.

The Obama administration denied pipeline operator TransCanada the State Department permit in 2015, citing environmental concerns. But four days after taking office in January 2017, Trump signed a memorandum inviting TransCanada to re-submit a permit application, as well as encouraging the State Department to expedite its decision.

This step gets Trump closer to fulfilling his promise to build the pipeline, but hurdles remain. The Nebraska Public Service Commission still has to approve the project, and protests from environmental activists and local landowners are expected.

Additionally, Trump said he wants "a piece of the profits," and it is unclear as of yet how Trump or the United States could demand some sort of compensation for building the pipeline.

For now, this promise remains In the Works.