Mexico’s Supreme Court deemed constitutional Thursday a controversial energy law pushed by President Andrés Manuel López Obrador that gives government-owned power plants preference over private competitors.

The law took effect in March 2021, but a number of private energy companies sought injunctions blocking enforcement. With the law ruled constitutional, the injunctions will now have to be resolved.

The law establishes that electricity must be bought first from government power plants, which use primarily coal, oil and diesel to produce energy. If demand requires it, additional electricity could be purchased from private wind, solar and natural gas plants.

Jesús Ramírez, presidential spokesman, celebrated the court’s decision. “History will judge those who betray the country and the interests of Mexican people,” he said via Twitter.

Critics, including the United States government, maintain the law will undermine competition in the sector, hurt the environment and violate free trade agreements.