WASHINGTON - Senate Democrats and drug policy groups pushing for a strong response to the heroin epidemic are growing increasingly concerned that Sen. Chuck Schumer (D-N.Y.) is dangerously politicizing the issue, risking what has been steady, if slow, bipartisan progress.

The good news for those suffering under the weight of the nation's heroin problem is that politicians are finally paying attention. The bad news is that some of the states that are in the most desperate need of help also happen to be home to some of the Republican senators Democrats would most like to knock off in 2016. And if the Democrats pick up enough seats, Schumer is poised to become Senate majority leader.

The opioid crisis has surged to become the deadliest drug epidemic in American history, taking the lives of nearly 30,000 people in 2014, with little sign of abating. It has hit hardest in rural, mostly white areas, and as the presidential campaign toured through Iowa and New Hampshire, the issue was elevated by the many voters who pressed candidates on it. A rare bipartisan Senate effort to deal with the issue has finally picked up momentum this month, but 2016 politics may intervene.

New Hampshire and Ohio have both been racked by the epidemic, and both Sens. Kelly Ayotte (N.H.) and Rob Portman (Ohio) are vulnerable in 2016. If they win reelection, the path to a Democratic majority is extremely difficult.

"Schumer woke up at some point in early February and said, 'How in the hell did we get ourselves in this position, where we're moving forward with one of the top legislative priorities of two of our top targets?'" quipped one Senate GOP aide.

Whether he'd seen it coming or not, Schumer held a press conference on Feb. 11 to rail on Republicans for not sufficiently funding the response. During the event, he roped the heroin epidemic in with Flint and Zika as examples of public emergencies that Republicans were ideologically unable to address, a performance that was picked up by Politico as political message-testing.

That same day, not coincidentally, a heroin bill being pushed by Portman and Ayotte, the Comprehensive Addiction and Recovery Act, passed unanimously through the Judiciary Committee. A series of policy changes and spending authorizations, the bill itself did not appropriate any money. In Congress, you must both "authorize" and also "appropriate" funds for money to be available for a program. In this case, money had previously been appropriated that could become available. Schumer, who is one of the bill's cosponsors, warned that if Republicans didn't immediately approve a $600 million emergency aid package put together by New Hampshire Democrat Jeanne Shaheen to go along with it, they couldn't claim to be serious about addressing the crisis. Asked at the press conference if Democrats would support the bill without the emergency $600 million, Schumer demurred.

That same day at the Judiciary Committee hearing where Portman's bill was voted on, Schumer made sure to praise the Democrats on the bill, but left out Portman and Ayotte. "I want to compliment the cosponsors, Senator Whitehouse and [Amy] Klobuchar on this committee, and our two other sponsors not on the committee for this bill. It's a very good bill. We have an opioid epidemic and I'm proud to be a cosponsor, but I want to make a point here: We have to walk the walk not talk the talk to just authorize," said Schumer, transitioning to a critique of the GOP penchant for cutting spending, making one of many references that day to Zika and Flint. "To just authorize money and to not actually put money to spend will do nothing to resolve the crisis. And this is becoming something that we see is a pattern."

Back at the press conference, the lead sponsor of the measure, Sen. Sheldon Whitehouse (D-R.I.), who Schumer had just praised, was noticeably absent. The senator was upset at how the situation was being handled, according to a Democratic aide involved in the issue. (A spokesman said Whitehouse wasn't able to make it; a Democratic leadership aide said Whitehouse approved of the Schumer event.)

The press conference got a little awkward. Shaheen was visibly uncomfortable, and asked to take the podium from Schumer for a moment, using the time to emphasize that CARA was a "strong, bipartisan bill." She added that she agreed with Schumer that the funds in her bill would strengthen the approach.

Schumer then headed back to the mic. "People who vote for the CARA bill," he said before he'd even arrived back at the podium, "and then vote against the Shaheen amendment and other amendments that will be brought on the floor are not really helping solve the problem."

Now, a leading liberal drug policy group is warning the Senate that the partisan turn in the heroin conversation is an unwelcome one. Though the letter doesn't single out Schumer -- letters addressed to the Senate tend to be as deferential as possible -- the message is clear. "[M]eaningful progress on the opioid and heroin epidemic is only possible when policymakers commit to moving forward in a bipartisan fashion," the letter from the Harm Reduction Coalition reads.

"We have appreciated the bipartisan spirit of collaboration with which Senate Committees have thoughtfully approached these issues, emblematized by the strong support in the Judiciary Committee and amongst the broader community for [CARA]. Harm Reduction Coalition requests that you honor this bipartisanship as you work to advance this bill to the Senate floor," reads the letter, which was sent this weekend to Senate leaders and provided to The Huffington Post by a Senate source.

Portman, for his part, agrees that money needs to be attached to the bill. Kevin Smith, a spokesman for Portman, noted that Portman, along with a bipartisan group of senators, successfully pushed for extra funding for the opioid crisis. That money, roughly $100 million, hasn't yet been spent, meaning it could be available for CARA. Portman, he said, is also open to additional money.

“Rob is for more resources to fight this crisis, and that's exactly what his bill calls for, not just here but going forward," Smith told HuffPost. "He is also happy to discuss more resources, but he believes that getting CARA done now is critical so we can begin to make a difference in the lives of families in Ohio and around the country.”

Aides to Portman, Whitehouse, Shaheen and Sen. Joe Manchin (D), whose home state of West Virginia is particularly hard-hit, are continuing to negotiate, and CARA could come to the floor as early as next week.

"First responders and treatment providers in New Hampshire and across the country, depend on the programs identified in this bill and provides them with urgently needed resources quickly," Shaheen spokesman Ryan Nickel said in an email. "Everyone on the frontlines of this crisis will tell you that they need help now and an emergency bill is the best tool Congress has to make that happen."

How Schumer's objection will play out remains to be seen. While drug policy groups are happy to take any money that's offered, several suggested that everything Shaheen was asking for -- and Schumer was demanding as essential -- wasn't necessary as emergency funding, and other parts of it weren't well-targeted.

Daniel Raymond, policy director at the Harm Reduction Coalition, authored the letter to Senate leaders. "I would take what I could get out of this process, but something in the 250-300 [million] range would mean each state ... has some money to work with. It's a little more modest than the Shaheen proposal, but it's not crazy," said Raymond, an advocate in the unusual position of saying that less money would be fine. (Raymond spoke to HuffPost on Friday before his letter had been sent to the Hill, and didn't mention the letter would be coming.)

Grant Smith, who works on legislation for the Drug Policy Alliance, another reform group, said that in particular, the more than $200 million in Shaheen's bill that goes toward law enforcement isn't compatible with the new public health approach to the issue. Another $85 million is earmarked for research by the Centers for Disease Control and Prevention and the National Institute on Drug Abuse. Both Raymond and Smith said their organizations were broadly supportive of research and prevention money, but that this funding wouldn't do anything for the immediate emergency. And finally, they both said, Shaheen's bill doesn't disperse money to states based on how bad the epidemic is there, but instead uses more standard formulas, and doesn't require money to be spent on fighting the opioid problem.

Even without the supplemental money, the CARA bill is a step forward, said Smith. "It definitely represents important strides despite the recent back-and-forth between some Democrats and some Republicans on this," he said. Smith praised the bill for emphasizing medication-assisted treatment, expanding access to naloxone, the overdose reversal drug, and for moving people away from the criminal justice system and toward treatment.

Even if the bill were to pass, it's not obvious that it would give Ayotte much of a boost at home. Her 2016 opponent, New Hampshire Gov. Maggie Hassan, has been outspoken on the heroin issue. Recently, she took the lead in a push by the National Governors Association that is more aggressive than anything the Senate is contemplating.

Dr. Kelly Clark, president-elect of the American Society of Addiction Medicine, says her organization sees CARA as a “down payment on really attacking the epidemic.” But she notes that neither CARA nor the Shaheen proposal include a provision to lift the cap on the number of patients a doctor can treat with buprenorphine (commonly sold as Suboxone).

Federal regulations, written under a drug-war mindset, stipulate that certified doctors can only treat 30 patients at a time during their first year prescribing the medication and 100 patients for the following years. Buprenorphine, along with methadone, is widely viewed as the best way to treat an opioid addiction, and both medications have been proven to lower overdose rates. But these drugs are out of reach for addicts living in the more rural parts of the United States. It is the only medication restricted in such a way.

CARA does try to shift the treatment toward medication-assisted treatment, authorizing funding to study the approach. But without lifting the caps, expanding access becomes difficult.

“Simply having additional federal funding is not going to be sufficient,” Clark said. “There’s still a lack of access to the most evidence-based treatment for opioid addiction, which is medication used in the treatment of opioid addiction. Funding from the federal government in and of itself will not increase access to that treatment. ... It’s imperative that this congress addresses that 100 patient limit.”

Senators negotiating a path forward are looking for ways to incorporate a bill by Sens. Ed Markey (D-Mass.) and Rand Paul (R-Ky.), both of whose home states have been battered by the epidemic. The Markey-Paul bill would raise the first-year cap from 30 patients to 100 and allow qualified nurse practitioners and physician assistants to prescribe the medication. It also would give doctors the chance to remove the patient cap after one year.

Across the board, though, advocates prefer the proposal put forward by the White House in its latest budget request of $1 billion, targeted toward reforming the treatment system and reducing barriers to medication-assisted treatment.

"What the president is proposing in his 2017 budget for addiction treatment looks better than what's coming out of CARA or the Shaheen/Schumer amendment,” said Dr. Andrew Kolodny, the chief medical officer for Phoenix House, an addiction rehabilitation nonprofit. “I'd like to see more than $1.1 billion, but it's a start ... I'm happy to see it. I wish we would have seen this sooner."

President Barack Obama’s funding proposal, though, must still wind its way through the legislative process.

A Democratic leadership aide said that Schumer, in the end, was not trying to play politics with the issue.

"The goal here is not to play politics, but rather to secure real federal resources that will make a much bigger impact on solving the problem," the aide said. "CARA is a good start, but those on the front lines treating this disease and combatting the drug trade need the resources to fight back, and Republicans have a terrible record when it comes to actually coming through when it’s time to fund these programs. By pushing for funding on the front end, we’re ensuring that the promises made in CARA are actually kept."

Update -- 2/22: On Tuesday, a new coalition sent a letter to Senate Majority Leader Mitch McConnell (R-Ky.), Majority Whip John Cornyn (R-Texas), Minority Leader Harry Reid (D-Nev.) and Schumer, calling for CARA to be debated and voted on. Nearly two pages of the letter are taken up by the names of groups from New York, clearly an effort to target Schumer (who, as the number three Democrat, was not included on the letter as a matter of course, but appears to have been added deliberately). On Wednesday, another letter went to McConnell and Reid making a similar request, this one signed by 130 organizations.