Here’s a classy way to slam people you disagree with: compare them to terrorists, dictators, and mass murderers.

Such was the focus of a recent billboard campaign by the Chicago-based Heartland Institute, a PR group that denies the existence of human-caused climate change. The only billboard that was actually displayed featured Ted Kaczynski (the Unabomber) and read, “I still believe in global warming. Do you?”

The message is clear: if a monster believes something, citizens of good moral standing should believe exactly the opposite. The Internet was quick to ridicule this philosophy, with parodies such as the following:

Similar billboards featuring Charles Manson and Fidel Castro were planned, but never publicly displayed. Heartland also considered putting Osama bin Laden on a future billboard. On their website, they attempted to justify this campaign:

The people who still believe in man-made global warming are mostly on the radical fringe of society. This is why the most prominent advocates of global warming aren’t scientists. They are murderers, tyrants, and madmen.

Given that a majority of Americans accept global warming, people did not take kindly to this campaign. Public outcry and negative media coverage led Heartland to cancel the project after 24 hours. However, their statement showed little remorse:

We do not apologize for running the ad, and we will continue to experiment with ways to communicate the ‘realist’ message on the climate.

Even though the campaign has been cancelled, the Heartland Institute continues to suffer financial repercussions. Dozens of corporate donors, including State Farm Insurance and drinks firm Diego (which owns Guiness and Smirnoff) have ended their support as a direct result of this campaign. Earlier in the year, Heartland lost financial backing from General Motors after internal documents exposed some of the group’s projects, particularly the development of an alternative curriculum to teach K-12 students that global warming is fake.

Will they recover from this failed campaign? Given Heartland’s reliance on donations, their prospects look poor. It seems that the Heartland Institute, previously one of the most influential mouthpieces for climate change denial, is going out with a bang.