The conservative free-market think tank Competitive Enterprise Institute started an online campaign Tuesday to urge President Trump to keep his campaign promise and withdraw from the Paris climate change agreement.

The campaign comes as the president's top advisers assemble Tuesday to decide whether or not to exit from the global accord, even though the White House has repeatedly said it won't make a decision until the end of May. The campaign also reflects the heightened disagreement between factions of the administration that reject and support leaving the deal on global greenhouse gas emissions reductions. Many scientists blame greenhouse gasses from burning fossil fuels for driving manmade climate change.

"The Paris climate treaty requires the United States to make drastic cuts in fossil fuel energy use by 2025, which will raise energy prices and slow economic recovery from our decade-long slump," said Myron Ebell, who leads the free-market group's environment program.

Ebell was Trump's former head of transition for the Environmental Protection Agency. In recent weeks, he has criticized Trump for appearing to be giving way to "swamp creatures," who are urging him not to leave the Paris Agreement.

On Tuesday, White House senior advisers, Cabinet members and their staffs will meet to see if they can form a consensus on whether to pull out of the deal. A cabal within the administration led by senior adviser and son-in-law Jared Kushner and Secretary of State Rex Tillerson favor remaining as signatories to the agreement.

Others, such as EPA Administrator Scott Pruitt, who also will attend the meeting, is pushing the administration to leave the agreement.

Ebell warned that not withdrawing from the Paris accord would undercut Trump's plans to undo former President Barack Obama's climate change agenda by making Trump's plans "vulnerable to legal challenges." It would give environmental groups a perfect argument before the courts in persuading federal judges, and even the Supreme Court, to rule in favor of the climate rules because they underpin the climate deal, even though it is nonbinding, Ebell has argued.

Ebell reiterated the message of an online ad campaign that the group will be airing, urging President Trump not to listen to "Washington's Swamp, but rather keep his campaign promise to get the United States out of the Paris climate treaty and send it to the Senate for vote."

The ad will be used to gain signatures for an online petition that will be sent to Trump, urging him to withdraw from the Paris agreement.

One of the key complaints that Trump raised during the presidential campaign was that Obama entered into the agreement in December 2015 without the consent of Congress.

The structure of the Paris agreement made it nonbinding, meaning that U.S. participation was not technically a treaty and therefore not subject to Senate approval. A vote by Congress is required for any international treaty.