The League of Conservation Voters’ political arm on Thursday started running a $100,000 TV ad that says St. Clair will “stand up to Donald Trump’s dangerous policies.” That spot comes on top of $300,000 worth of issue advertising from a nonprofit called the Maine Outdoor Alliance.

The group can’t tell viewers to vote for St. Clair. Instead, it has promoted the Katahdin Woods and Waters National Monument and praised St. Clair for his efforts to push for its creation.

The monument, although still controversial in some parts of the state, is a key part of what St. Clair is running on in the primary. His mother, conservationist and Burt’s Bees co-founder Roxanne Quimby, purchased nearly 100,000 acres of former timberland in the North Woods and donated it to the federal government with the goal of making it a national park.

But her desire to close the area to hunting, snowmobiling and logging initially angered some local residents. Maine’s congressional delegation refused to introduce legislation to make it a national park. St. Clair stepped in, announcing that part of the conserved land would be open to hunting and snowmobiling. He pressed former President Barack Obama to make the land a national monument, which he did in August 2016.

The Maine Outdoor Alliance, which was founded in March, doesn’t have to disclose its donors and cannot coordinate with St. Clair. But as the Bangor Daily News has reported, the group’s only listed officer on documents filed with the Maine secretary of state was also the best man at St. Clair’s wedding. The local press has also highlighted that one of the consultants Quimby hired for the monument campaign — Montana-based Barrett Kaiser — is linked to the firm that bought the airtime for the Maine Outdoor Alliance’s ads.