But Tim Young, associate regional director for the National Parks Conservation Association, said the Antiquities Act is an important power presidents have to take immediate action to protect areas.

"We have nationally significant resources that are under pressure from many things, and this provides a tool to protect those before those can be lost for future generations, and you can respond rapidly if there is a particular environmental threat," he said.

Still, Young said there is a balance between the executive power and legislative branch, as Congress has the ultimate authority to fund a monument or create a national park.

"The Antiquities Act has been exercised quite sparingly, and Congress still has to validate those decisions if they are going to become national parks," he said.

That push and pull came to a head in the latter years of the Clinton administration, when President Clinton used the Antiquities Act to create a slew of national monuments in Utah.

Some lawmakers, including the Wyoming congressional delegation, balked, saying the act gives too much power to the president, usurps power from states and eliminates public process.

Thomas said at the time he would draft a bill opposing the Antiquities Act.