Mr. Trump said he spoke with Mr. Marino and praised him as “a fine man” who “feels very strongly about the opioid problem.” Speaking on Fox News Radio, the president said, “If there’s even a perception that he has a conflict of interest, he doesn’t want anything to do with it.”
Mr. Trump has said he will formally declare the opioid crisis a national emergency next week in an effort to draw more attention to the problem and free up resources to fight it. He has not disclosed other elements of his plan. And critics said that Mr. Trump would have made the problem worse had Congress passed his proposal to repeal the Affordable Care Act, under which lower-income Americans get treatment.
“The fact that he was nominated in the first place is further evidence that when it comes to the opioid crisis, the Trump administration talks the talk, but refuses to walk the walk,” Senator Chuck Schumer of New York, the Democratic leader, said on the Senate floor after Mr. Marino’s withdrawal. “The bottom line is, this congressman supported President Trump, but is the wrong person for the job.”
But the congressman’s fall also presented tough questions for Democrats, who supported without dissent the same industry-friendly legislation that Mr. Marino championed. The bill passed both houses of Congress last year with unanimous consent and then was signed into law by Mr. Obama.
“Lest we forget, President Obama signed the bill into law on the advice of his own D.E.A. administrator,” said Senator Orrin G. Hatch, Republican of Utah who pushed the legislation with Mr. Marino.
The legislation and Mr. Marino’s role were featured in a joint investigation by CBS News’s “60 Minutes” and The Washington Post on drug industry influence in Washington. The law changed the standard required before the Drug Enforcement Administration could freeze suspicious sales of painkillers to cut the flow of opioids into the black market.
Instead of requiring a finding that shipments posed an “imminent danger” to the community, the D.E.A. now has to conclude that they represent “a substantial likelihood of an immediate threat,” according to the Post.
The drug and medical industries complained that D.E.A. enforcement efforts were curbing the availability of legal painkillers for patients who legitimately need them. In his statement on Tuesday, Mr. Marino called the legislation “a balanced solution for ensuring those who genuinely needed access to certain medications were able to do while also empowering” law enforcement efforts.
The D.E.A. and the Justice Department accepted the change after beating back what they considered more problematic versions. Law enforcement officials were worried about a proposal to require the D.E.A. to find evidence of intent before it could freeze suspicious shipments, a provision that would have made it much harder to take action. That was kept out of the final version.
Once the D.E.A. and the Justice Department signaled they could live with the legislation, lawmakers from both parties went along. When it was sent to Mr. Obama, the White House drug policy office conferred with the Justice Department and D.E.A. “They indicated that they did not see this bill as substantially diminishing any legal authority to pursue investigations,” said Michael Botticelli, the drug czar at the time. “As a result, we deferred to D.E.A. as is common practice.”
Mr. Obama’s office referred questions to Mr. Botticelli on Tuesday, but there was a division among former officials of the last administration. Some argued the change was not especially meaningful and that they were not aware of any instances when it prevented the D.E.A. from taking action that it would have taken before the law.
But a draft article by the D.E.A. chief administrative law judge concluded otherwise and some Obama administration veterans expressed chagrin that the legislation had not been flagged. In hindsight, they said the D.E.A.’s acceptance of the legislation underscored concerns that the agency was not aggressive enough in tackling the spread of opioids.
Senator Claire McCaskill, Democrat of Missouri, said she was introducing legislation to overturn the law. Mr. Trump did not say whether he would support such a move.
The law was a priority of the drug industry, which spent more than $100 million lobbying Congress between 2014 and 2016, according to The Post. Mr. Marino received $100,000 in campaign contributions from political action committees affiliated with the industry. But the Pharmaceutical Research and Manufacturers of America said in a statement that it “did not support or lobby in favor” of the bill and later on Tuesday evening called for it to be repealed.
Fueling the dispute was a personality clash involving Mr. Marino and a former top D.E.A. official, Joseph T. Rannazzisi. Known as a hard charger who pushed for tougher enforcement against drug distributors, Mr. Rannazzisi was admired by some for his zeal but criticized by others for being unwilling even to meet with drug companies before taking enforcement action.
During consideration of an earlier version of the legislation, Mr. Rannazzisi said told congressional aides that lawmakers who supported it would have “blood on their hands,” according to former officials briefed on the conversation. Mr. Marino heard about that and grew furious. During a hearing, he complained that Mr. Rannazzisi had accused bill sponsors of “supporting criminals,” adding, “This offends me immediately.”
Mr. Rannazzisi, who left the agency in 2015 and could not be reached on Tuesday, denied to The Post that he said that. “I said that this bill is going to protect defendants that we have under investigation,” he told The Post. “And if they don’t like the truth, well, I don’t know what to tell ‘em.”
The former officials said the episode spurred Mr. Marino’s efforts to pass at least some version of the bill. In his statement on Tuesday, Mr. Marino lashed out at Mr. Rannazzisi. “Specifically, I cannot allow false allegations made by a former D.E.A. employee, who resigned from the agency,” Mr. Marino said, suggesting that “his assertions may be motivated by financial self interest.”