Opening statements in the country’s first trial over whether a pharmaceutical company is liable for the opioid crisis began as a battle between fire and ice: Lawyers for Oklahoma, a state brought to its knees by addiction and overdose deaths, heatedly accused Johnson & Johnson of creating a deadly demand for the drugs, while the company coolly responded that it had acted responsibly and lawfully in its quest to offer relief to chronic pain patients.

The trial, heard by a judge without a jury but livestreamed to the public, is being closely watched not only by those affected by prescription opioid addiction, but also by lawyers in almost 1,900 similar federal and state cases nationwide. Two other defendants who manufacture opioids settled with Oklahoma — Purdue Pharma will pay $270 million, Teva Pharmaceuticals, $85 million — leaving only J & J on trial.

The state directly confronted what many legal experts have predicted will be the highest hurdle in the case: connecting one manufacturer of opioids to the cascading harms wrought by the entire industry.

J & J pushed back hard, arguing that the state itself looked the other way as its own drug review board and prescription monitoring program for years neglected to swoop down on sources of diverted opioids. In addition, it said, Oklahoma could not tie any death directly to the company’s products — Duragesic, a fentanyl patch, and Nucynta, an opioid pill it no longer makes.