Colorado law enforcement officials have sent a letter to Gov. John Hickenlooper saying they are worried that the state could botch regulations for recreational marijuana.

In the letter, sent Tuesday, the officials say they fear there is “the potential for the passage of marijuana laws which are a grave disservice to the public.” At the Capitol, the leaders say, there is a “concerted effort to continue to undermine law enforcements effort to keep our youth safe and stop diversion.”

“We have strong concerns that if Amendment 64 is not implemented properly, we will become the nation’s supplier of choice for marijuana,” the officials wrote in the letter, signed, “Sincerely yours on behalf of the public safety which we are sworn to protect.”

The letter was sent by members of the Colorado Association of Chiefs of Police, the Colorado District Attorneys Council, the County Sheriffs of Colorado and the Colorado Drug Investigators Association. The groups sent the letter to Hickenlooper, leaders in both the Colorado House and Senate and state Attorney General John Suthers.

Provocatively, a copy of the letter was also sent to U.S. Attorney John Walsh, whose office considers all marijuana illegal and could move to shut down the state’s nascent system of regulated pot stores.

The letter is the latest sign of a breakdown in consensus at the Capitol on the best way to regulate recreational marijuana — which Colorado voters legalized in November with the passage of Amendment 64. While Democrats, Republicans, law enforcement groups, marijuana advocates and others worked together on a special marijuana task force to draft proposed regulations, the debate over the regulations has become a divisive, partisan affair.

On Tuesday, the state House gave its final approval to a bill setting proposed tax rates for retail marijuana sales, on a 37-27 party-line vote. The bill, House Bill 1318, proposes a 15 percent excise tax and an initial 10 percent sales tax on pot sales. Republicans said the rates are too high and that voters — who have to give the final OK for the taxes — may balk.

On Monday, the House gave final approval to a bill laying out the industry structure for marijuana business, in another vote that broke largely on party lines.

“It is extremely unfortunate they became partisan bills when it was a bipartisan process,” said Rep. Dan Pabon, a Denver Democrat who was the sponsor of the bill passed Monday, House Bill 1317.

Both bills now head to the Senate.

Another bill — Senate Bill 283, which has also been contentious even though it contains only “consensus” proposals for marijuana regulation — is scheduled to be debated Wednesday in the Senate.

The law enforcement groups cite two specific concerns about the bills in their letter to Hickenlooper. The groups say they are upset that funding training for police officers to better identify drugged drivers has been made optional and that funding was also cut for studies to examine the consequences of marijuana legalization.

“Simply put, money cannot drive this decision,” the groups state in the letter.

The groups also say they worry lawmakers may strip out a provision in HB 1317 that creates a scientific definition of stoned driving. A separate bill on that subject died in a Senate committee, but lawmakers in the House inserted it into HB 1317.

And the groups say they are wary of potential efforts to weaken a bill on drug-endangered children, which proposes that children who are present in homes where marijuana is being grown could be considered victims of child abuse — even if the pot is grown in compliance with state law. That bill, Senate Bill 278, is also awaiting a debate in the full Senate.

The legislature has until May 8 to approve all the bills before the session ends.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold