Last week, Robert F. Kennedy Jr., once a prominent figure of America’s environmental movement, suspended his independent run for the White House and endorsed former President Donald Trump.

On its face, the announcement seemed jarring. Trump has called climate change a “hoax” and, during his time in office, worked to unravel more than 100 environmental policies and regulations. Kennedy, who worked for years as a lawyer fighting against polluters, had claimed he would have been the “best environmental president in American history.” Most experts consider Trump’s presidency to be among the most punishing to the environment in recent history.

In April, as Lisa Friedman reported, the political arm of the Natural Resources Defense Council, a nonprofit group, took out full-page newspaper ads in a number of swing states in which nearly 50 of Kennedy’s former colleagues asked him to “honor the planet” and withdraw from the race because they feared his candidacy could help Trump.

So how did Kennedy end up here?

Kennedy’s campaign didn’t respond to my questions about how he squares his life’s work with his support for Trump. But Kennedy’s announcement didn’t seem to surprise those who have worked with him or followed his environmental career.

Today I want to explain why.

Kennedy’s environmental record

Kennedy, 70, is a son of the former attorney general and presidential candidate Robert F. Kennedy, and a nephew of former President John F. Kennedy.

Kennedy loved animals and nature as a child, but his work on environmental issues started in the 1980s when he was required to do community service after being sentenced to probation in connection with heroin charges, according to a recent profile in The New Yorker. That’s when he started volunteering at the Natural Resources Defense Council, which at the time was a small environmental group. Kennedy worked as a senior attorney for the council for about 28 years.