“Before this, there was talk, but only talk, of separating,” one source at the Washington office said. “But the decision of our sponsors to withdraw obviously forced our hand.”

Insurance companies withdrew support after the Heartland Institute's billboard campaign that sparked controversy by comparing those who believe in global warming to Unabomber Ted Kaczynski. Similar billboards featuring Charles Manson and Osama Bin Laden were planned, but Heartland suspended the ad campaign after widespread condemnation, including strong criticism from its supporters.

Industry members withdrawing support for the Heartland Institute include the Association of Bermuda Insurers and Reinsurers—which represents 22 Bermuda-based companies—State Farm, XL Group, Allied World Assurance and, according to an SNL Financial story, RenaissanceRe Holdings Ltd and USAA.

In ABIR's letter to Heartland Institute President Joseph Bast Friday, Bradley Kading, ABIR president, said the Bermuda association would “disavow” its ties with Heartland.

Kading says ABIR's action was done independently, and that ABIR did not know at the time the letter was written about a campaign by Forecast the Facts to force large companies to drop out of Heartland.

Forecast the Facts took credit for ABIR's decision in a press release Tuesday. It says it is an organization “dedicated to ensuring that Americans are accurately informed about climate change.”

Insurers use Heartland's Washington unit as part of their efforts to expand market-based solutions to catastrophe issues, including providing a role for reinsurers in funding the National Flood Insurance Program.

Heartland has experts on staff who closely track federal and state efforts to deal with flood and catastrophe issues, including state-based earthquake and windstorm funds.

It has satellite offices in Austin, Texas; Tallahassee, Fla.; and Columbus, Ohio.

Its key Washington personnel include Eli Lehrer, who heads the Washington unit, and Ray Lehmann, deputy director.

While Heartland's Washington unit is focused on financial and insurance issues, global warming is apparently a primary issue with Heartland officials in Chicago.

On its website, Heartland claims that “the most prominent advocates of global warming aren't scientists. They are murderers, tyrants, and madmen” who are “willing to break the law and the rules of ethics to shut down scientific debate and implement their left-wing agendas.”