It’s a scene that continues to unfold in Washington state: A helicopter hovers low over the trees, deep inside a park in the Cascade Mountains; a SWAT team dressed in Kevlar rappels from the chopper to the ground; other officers, federal agents and state environmental officials move toward the site on foot, alert for armed guards, booby traps and razor fencing.

The targets of these taxpayer-funded efforts aren’t terrorism suspects or dangerous fugitives — they are marijuana plants.

The Drug Enforcement Administration (DEA) has for decades poured millions of dollars into a nationwide marijuana-eradication program, and the effort continues even in Washington, where the drug was legalized for recreational use in 2012. Financial documents obtained from the DEA show that in fiscal year 2016, Washington was the nation’s fourth-largest recipient of eradication funding, at $760,000. According to the most recent data, each plant the state destroys costs taxpayers $26.49, over six times the national average.

Washington’s funding has fallen 28 percent over the last three fiscal years, from about $1.1 million. But funds for the DEA’s marijuana-eradication program have seen larger cuts in other states where the drug has been legalized, according to the financial documents. Colorado’s funding dropped to zero over the past two fiscal years. Oregon’s budget has been slashed by 80 percent — from $1 million to $200,000 — during the same time.

“While the DEA’s Cannabis Eradication/Suppression Program has been in effect nationwide for three decades, the recent trend in state laws to legalize and decriminalize the production, distribution or consumption of marijuana calls into question the necessity of such a program,” the letter states.

One of the letter’s signees, U.S. Rep. Ted Lieu, D-Calif., proposed legislation last year that would have cut the eradication program’s funding in half. The effort failed.

Lieu, in an interview with The Seattle Times before the November election, said that legalization of recreational marijuana in California — the nation’s top cultivator — would force the DEA to reassess the feasibility of trying to suppress the country’s supply. The election saw voters in California, Maine, Massachusetts and Nevada approve measures to legalize marijuana for recreational use. Voters in Arkansas, Florida, Montana and North Dakota approved the drug for medical use.

Legalization will accelerate discussions of whether the drug’s national prohibition can be maintained, Lieu said.

“I don’t believe the arguments that this program is needed. From a taxpayer’s standpoint, it doesn’t make any sense that Washington state is still spending so much money on marijuana eradication,” Lieu said. “There are so many more worthwhile uses for it.”

Lt. Chris Sweet of the Washington State Patrol has managed the state’s eradication program since 2013, mainly by requesting and administering federal funds. Sweet said that when he attends law-enforcement conferences, he’s frequently asked how he can operate a marijuana-eradication program in a state where the drug is legal.

“I hear it all the time: ‘You guys still have an outdoor-eradication program when you’re a legalized state? How does that make sense?’ ” Sweet said.

Eradication remains a law-enforcement priority because Mexican drug cartels may have moved their marijuana-growing operations north of the border, where the climate produces higher-quality plants, Sweet said. These organizations tend to operate on swaths of public land, often in mountainous regions, where detection of large crops is difficult.

The abundance of good growing terrain along the eastern slopes of the Cascades has led the Sinaloa Cartel of Mexico — considered the world’s most powerful drug-running operation — to operate in that region for some time, according to a recent joint report from the DEA and Department of Justice.

The presence of Mexican drug cartels might explain why Furadan, a pesticide banned in the United States and “only made south of the border,” has been found on Washington’s illicitly grown marijuana crops, Sweet said. California authorities have also cited the pesticide as evidence of Mexican involvement in grow operations there. Starting this year, Sweet said, officers removing illegal marijuana plants must wear protective suits and be accompanied by Department of Ecology agents.

The DEA’s eradication program gained national attention in September after a helicopter, a bevy of police vehicles, state police officials and National Guard troops descended upon the home of an 81-year-old Massachusetts woman to haul off a single marijuana plant growing in her garden.

However, small growing operations are not typically targeted by the program. The average size of a Washington crop bust in 2015 was 609 plants; the average size nationally was 519, according to DEA records.

There have been roughly 57,000 plants eradicated in Washington so far this year, a 63 percent increase over 2015’s total haul. Sweet believes the involvement of Mexican drug cartels helps explain the rise in plant discoveries this year.

“No one had a crystal ball about how legalization would affect our outdoor growing, but with the spike this year, we’ll have to see what the coming years bring,” he said. “Is it a freak thing? It’s too early to tell.”

But the DEA’s records show that the number of plants found in Washington this year is almost identical to the number found two years ago, and down significantly from the 346,484 plants eradicated five years ago. Nationwide, the records show a nearly 70 percent decrease in the number of grow sites eradicated between 2010 and 2014.

Morgan Fox, communications manager of the Marijuana Policy Project, the largest U.S. nonprofit dedicated to marijuana reform, said the best way to limit the impact of drug cartels is to “eliminate the illicit market, and make it not worth it economically. That’s what we see legalization doing.”

“Law-enforcement organizations are loath to give up on funding sources, so there are times there is a concerted effort to tell a dramatic story,” Fox said. “Marijuana eradication is just playing whack-a-mole.”

In justifying the program’s continued existence in Washington, Sweet cited the need to fight Mexican gangs, and to mitigate the environmental damage caused by grow operations. The fact the program has been slashed in Colorado and Oregon is ominous to him, he said.

“We’ve seen the proposals in Congress, and the public perception, and the adage that this is money that can be used for other programs, like education and treatment,” Sweet said. “That’s definitely a big concern.”

For Fox, the fact eight more states legalized pot this November illustrates the program’s increasing irrelevance. After alcohol’s prohibition, he said, a criminal element remained in the industry for a while but diminished as the legal market established itself.

“We don’t see illicit criminal organizations planting secret vineyards on national parks when the market has been made legal for wine,” said Fox. “There’s still some illegal moonshine stills around the country, but it’s not a big issue. This is where we’re headed as a country.”