Washington Gov. Jay Inslee has announced he's ending his 2020 Democratic presidential bid, saying it has become clear he won't win.

Mr. Inslee had centered his campaign around climate change, calling it “the most urgent challenge of our time.”

Back at his kickoff campaign in March, Inslee said, "This is our moment to put the greatest threat to our existence, to our economy, to our health, at the very top of the nation's agenda."

He put out a detailed 10-year plan on how he’d move the country to clean energy, spurring other candidates to put out their own plans.

Butting heads with the Democratic National Committee, he demanded that the organization hold a debate focused on climate change.

The DNC told him to take a hike in June, but CNN announced soon after that it would hold a town hall on the issue with the 2020 candidates in September.

Inslee, however, did not meet the polling criteria the network used for the event -- a minimum of 2 percent in four DNC recognized polls -- and was not on the list of attendees the network announced on Tuesday.

While Inslee said Monday that he had reached the 130,000 donation threshold for the next Democratic debate, his lack of qualifying polls would likely have kept him from the debate stage as well.

Inslee is the third major candidate in the sprawling field to exit the race after Rep. Eric Swalwell of California and former Colorado Gov. John Hickenlooper.

 Like those two, Inslee had virtually zero name recognition outside of his home region, Washington and the Pacific Northwest.

 Now, more calls are coming for him to pay back the millions of taxpayer dollars spent on his security detail, via the Washington State Patrol. His campaign has been silent on that matter.