The idea was straightforward. Washington Gov. Jay Inslee would make his mark in the 2020 Democratic presidential primary field by focusing relentlessly on one issue: climate change. He’d be the climate change candidate, elevating the subject to prominence in the party’s contest and, he clearly hoped, elevating his own chances of winning the nomination.

It didn't work. On Wednesday, about six months after he announced his candidacy, Inslee dropped out of the race.

A natural question arises as a result: Do Democratic voters just not care that much about climate change? Was Inslee dropping out a function of voters’ relentless focus on beating President Trump instead of specific policy issues — even one as pressing as the erosion of the global environment?

The short answer is probably no. Inslee backing out was, instead, probably a function of both his own weakness as a candidate and the fact that climate change is an issue of importance to Democrats.

Inslee’s strategy wasn’t an outrageous one. A case can be made that Trump’s success in the 2016 Republican primary was predicated on a relentless focus on a single issue. In his case, that was immigration, a subject he broached within the first minutes of his campaign announcement in the stark, divisive terms that have become a hallmark of his political rhetoric.

The difference in effectiveness between Inslee’s and Trump’s single-issue campaigns doesn’t really lie in the priorities they embraced. In each case, there was chatter about the issue before they became candidates. In January and February, before Inslee entered the race, there were about 2,400 articles mentioning the Democratic primary and climate change, according to a search of Nexis. In the two months before Trump’s entry, there were about 2,600 articles dealing with immigration.

The difference, really, was one of approach. Trump framed immigration in much starker terms than his opponents did, echoing the hard-line rhetoric that was popular in conservative media but not on Capitol Hill. He advocated a politically problematic approach that his opponents — politicians — shied away from. The result for voters was a sense that Trump was willing to say what others were afraid to about a subject that, for many of them, was a priority.

Inslee’s passion for fighting climate change is unquestionable, but it wasn’t conveyed in the same way. The governor lacked Trump’s ability to seize media attention, which muffled his message. But given a platform — the Democratic primary debates — climate change often seemed like an afterthought.

The first question he was posed in the June debate dealt with income inequality. His response?

“Well, I’m a little bit surprised. I think plans are great, but I’m a governor. And we’ve got to realize the people who brought us the weekend, unions, need — are going to bring us a long overdue raise in America. And I’m proud of standing up for unions. I’ve got a plan to reinvigorate collective bargaining so we can increase wages finally. I marched with the SEIU folks. It is not right that the CEO of McDonald’s makes 2,100 times more than the people slinging hash at McDonald’s.”

Nothing about climate change at the outset. He then transitioned into a discussion about putting people to work on clean energy projects, without identifying climate change by name as a motivation for that push.

After answering questions about health insurance and immigration without mentioning climate change, Inslee was asked about climate change specifically because he had stated that it was his reason for running.

“We’re here in Miami, which is already experiencing serious flooding on sunny days as a result of sea level rise,” moderator Rachel Maddow said. “Parts of Miami Beach and the Keys could be underwater in our lifetimes. Does your plan save Miami?"

“Yes,” Inslee responded, “first by taking away the filibuster from [GOP Senate Majority Leader] Mitch McConnell, to start with. We have to do that.”

Put more directly: The image Inslee presented in the debate was of a Democrat seeking the nomination, not as someone for whom climate change was an issue of existential importance. Compare that with Trump, whose false excoriations of immigrants as criminals and inherent dangers to the country were viscerally resonant with Republican voters.

It's important to recognize that Trump's pitch on immigration, such as it was, was unique. No one else was saying “build a wall” or “Mexican immigrants are rapists,” for good reason. But it was inevitable that other Democratic candidates would release plans for addressing climate change, as they did. It seemed as though Inslee's most extreme position on climate change relative to the field was identifying climate change as the purpose behind his campaign.

Had Inslee made more of a splash in that debate, had he conveyed the passion and urgency that he said motivated his campaign, who knows? Perhaps a few percentage points would have been knocked loose in a few polls. But he didn’t.

Of course there were also greater head winds that Inslee (and most other candidates) faced: a Democratic electorate worried more about beating Trump than anything else. Former vice president Joe Biden’s climate proposals are mostly reheated policies from the administration of Barack Obama, and most of his other proposals are similarly moderate. But Biden leads in large part because he’s considered the best bet to send Trump back to Trump Tower.

The greatest mark Inslee made in the race may have been in advocating for a primary debate centered on climate change as an issue. It was an idea that Inslee advocated forcefully and, after being rejected by the Democratic Party, was embraced by CNN. That debate will happen next month, but Inslee’s support in the Democratic primary wasn’t robust enough to earn him a spot.

Polling from YouGov found that in March, shortly after Inslee entered the race, three-quarters of Democrats said that climate change was a very serious problem. In mid-June, after Inslee had been in the race for more than two months, there was no statistical difference in that figure.

Inslee was caught in a Catch-22: He needed to break out to get attention for his cause but couldn’t break out without attention being focused on his cause. Given the chance to make his case, he instead offered debate viewers standard-issue Democratic-candidate patter — even as his opponents mirrored his rhetoric (if not his detail) on his core issue.

Given that, his departure was inevitable.