Last fall, he opened an investigation into whether ExxonMobil deliberately concealed the fact that its scientists determined that consuming fossil fuel could cause changes in the global climate.
The move came in response to stories published by Inside Climate News and The Los Angeles Times alleging that ExxonMobil, despite these findings, played a leading role in stoking skepticism about climate change beginning in the 1990s.
This all fit neatly into a narrative embraced by corporate antagonists and environmental activists: ExxonMobil, like tobacco companies in previous decades, spread untold millions of dollars among right-wing groups to deceive the public with bogus science.
In the months that followed, attorneys general from 17 states voiced support for the investigation. The hashtag #Exxonknew signaled that the elusive white whale had met its match.
But then facts complicated the narrative.
For starters, ExxonMobil scientists have indeed been looking into climate change for years, and the company has been publishing its research, not hiding it. In the context of a public-policy debate, the company has merely insisted on rigorous scrutiny of the science underpinning legislation aimed at fossil fuel use.
In congressional testimony in 2010, ExxonMobil Chief Executive Rex Tillerson said that the company acknowledged that humans were affecting the climate through greenhouse gas emissions but cautioned that it wasn't yet clear "to what extent and therefore what can you do about it."
On a tactical level, Schneiderman and his allies overreached.
Massachusetts, New York and the Virgin Islands sought subpoenas for vast troves of emails and other communications from several conservative and libertarian research and advocacy organizations, such as the Competitive Enterprise Institute. The groups pushed back, arguing that Schneiderman's fishing expedition was tantamount to the criminalization of Constitutional free speech.
ExxonMobil, which has provided hundreds of thousands of pages of documents to New York, counter-sued.
In June, the Virgin Islands' attorney general withdrew a suit filed under the RICO statute. Using RICO worked against tobacco companies because they did, in fact, conspire to hide evidence of the health hazards of smoking.
It didn't work for ExxonMobil though.
As The New York Times reported, ExxonMobil "published extensive research over decades that largely lined up with mainstream climatology."
Schneiderman has started backing away from the contention that ExxonMobil deceived shareholders about climate science. He is looking into whether ExxonMobil's executives are misstating the value of oil in the ground as they likely figure future laws and regulations will prevent that oil from being tapped.
What is next?
Will Schneider investigate Ben and Jerry's for failing to disclose that anti-obesity guidelines could one day depress ice cream demand?
The fact is, companies make forecasts based on current information. They adjust forecasts as facts change.
Sometimes, forecasts are wrong and shareholders lose money. Other times, failure to see the future results in a windfall.
Either way, being wrong isn't fraud. If there is oil in the ground that can be recovered and used and if laws to keep it there are far from imminent or inevitable, these deposits must be taken into consideration with regard to future revenue and profits.
Still, buoyed by the idea that it would be impossible to burn all the oil, Schneiderman, like Herman Melville's dogged Captain Ahab in Moby Dick, is trying all things.
He told The New York Times, "The older stuff really is just important to establish knowledge and the framework and to look for inconsistencies."
Convict first. Ask questions later.
The "older stuff" isn't sticking because the record shows that the company was upfront is disclosing what its scientists found. There is no evidence of conspiracy or fraud.
And running afoul of the Constitution won't uncover it. It is hard to see how the new tack will work.
It is true that company executives have pushed back against policies that would effectively shut the company down, and they have offered forecasts that assume such policies won't be enacted in the immediate future.
These executives are doing the job that shareholders hired them to do. If they did otherwise, then shareholders or Schneiderman should sue.
In the end, his fishing expedition won't land the proverbial white whale. Instead, his taxpayer-funded exploratory search continues to excavate facts that the energy giant already made publicly available.