A defiant response by Pennsylvania and New Jersey lawmakers from across the political spectrum followed an announcement Thursday by the Trump administration that it was rescinding an Obama-era policy that had paved the way for legalized marijuana to flourish in states across the country.

"I'm a Republican and I don't understand this," said State Sen. Mike Folmer of Lebanon, who was a cosponsor of the bill that legalized medical marijuana last year in the Keystone State. "I think it's cruel. If you think this is going to make America safe, cut me a break. This decision is just dumb."

Folmer's anger came in the wake of a memo issued by Attorney General Jeff Sessions in which he stated that he was ending the hands-off policy that had steered U.S. agencies on the enforcement of federal marijuana laws.

"Previous nationwide guidance specific to marijuana enforcement is unnecessary and rescinded, effective immediately," Sessions wrote. Instead, Sessions said he will let U.S. prosecutors decide how aggressively they want to enforce federal marijuana law in states that have dropped prohibitions on the plant and its products.

The announcement came without warning, though only days after California launched what is expected to become the world's largest market for legal marijuana. The move sparked fears of a potential federal crackdown on the burgeoning legal marijuana industry and the eight states where recreational use has been approved by voters.

Federal law has banned marijuana since 1937. But in the last decade 29 states and the District of Columbia have relaxed or eliminated laws restricting its use.

Polls show an overwhelming majority of Americans, 94 percent, believe the drug should be legal for medicinal purposes. About 62 percent nationwide support adult recreational use.

In 2013, the Obama administration took a stance that it would not stand in the way of states that legalized marijuana, as long as state officials kept it from migrating to places where it remained outlawed and out of the hands of children and criminal gangs. The Obama-era policies were created after Gov. Christie sent a letter to the Department of Justice in 2013 saying he would not implement the Garden State's medical-marijuana program without clarification.

Sen. Cory Booker (D., N.J.) addressed the Senate floor Thursday afternoon, echoing remarks he made when he introduced a bill to legalize cannabis federally in August.

"This is an attack on our most sacred ideals," Booker said. "It is a failure of this administration, who said, as our president did during his campaign, that he would honor what states are doing; it's a betrayal by our attorney general, who gave a commitment to at least one Republican member of this body [that he would not make marijuana a priority], but mostly significantly it hurts Americans."

New Jersey and Delaware have had medical-marijuana programs for several years. Pennsylvania, which is set to make medicinal cannabis available in the coming months for patients suffering from any one of 17 serious health conditions, is embarking on an ambitions medical program that will allow for research by the state's health systems. It is unclear how Sessions' move will impact the state programs.

Gov. Wolf vowed in a statement to protect patients in Pennsylvania "from any overreach by the federal government."

"I will continue to protect cancer patients, kids with epilepsy, veterans with PTSD and all Pennsylvanians seeking relief with legal medical marijuana," Wolf said. "We legalized medical marijuana in an overwhelming and bipartisan fashion, and we are months away from getting this medicine to patients who need it."

Sen. Bob Casey (D., Pa.) said he had "serious concerns" about how the decision could disrupt Pennsylvania's nascent medicinal program.

"Pennsylvanians, including many children, are being prescribed medical marijuana by their doctors for serious illness," he said. "Bureaucrats in Washington should not interfere."

A spokeswoman for Sen. Pat Toomey (R., Pa.) said that his staff was reviewing the legal implications but that the senator "continues to believe that the federal government should help facilitate research into marijuana for legitimate medical purposes."

In the Garden State, Gov.-elect Phil Murphy won on a platform that included legalizing adult recreational use. In a statement, his administration asserted its right to proceed.

While Sessions has set an agenda that follows Trump's top priorities on such issues as immigration and opioids, the changes to cannabis policy reflect his own concerns. Trump, on the campaign trail, once stated decisions about marijuana should be left to the states, but the president is known to change his mind on a whim.

Lawyers, entrepreneurs, and activists in the Philadelphia regions also reacted to the Sessions decision.

"Will Sessions single-handedly crush a $7.2 billion industry spanning 30 states, generating millions in taxes, and providing tens of thousands of jobs?" said Steve Schain, an attorney with the Hoban Law Group, a national firm with dozens of marijuana business clients.

"I would be surprised if they start to raid dispensaries and growing operations," said Beth Moskow-Schnoll, a former federal prosecutor who is now a partner at Ballard Spahr with a focus on the interplay of federal and state laws on marijuana.

"It would be so politically unpopular and why would they spend their resources doing that?" she asked. "Sessions may more subtly send out letters to landlords of facilities that house dispensaries or growing operations and tell them they'r ein violation of federal law and subject to forfeiture because they're facilitating the operation of an illegal business."

Lindy Snider, a cannabis-industry investor who is prominent in Libertarian circles, said rescinding the Obama-era policy "makes absolutely no sense."

"I'm so angry about it," Snider said. "The government is supposed to operate at the will of the governed. That's just part of the American Constitution. This should not be about Jeff Sessions' opinions. Over 50 percent of Americans say legalize this. He better have a damn good plan."

Cannabis-industry analysts largely shrugged at the news.

"Despite the negative headlines, we do not think this will result in a meaningful change relative to the current, more-lenient Obama-era policy, and it will not affect the industry's trajectory," Stefanie Miller of Height Securities told Bloomberg News.

Another analyst, Isaac Boltansky of Compass Point, told Bloomberg the policy shift would further hamper the industry's access to traditional banking.

Sessions, who has assailed marijuana as comparable to heroin and has blamed it for spikes in violence, had been expected to ramp up enforcement. Cannabis advocates argue that legalizing the drug eliminates the need for a black market and would likely reduce violence, since criminals would no longer control the marijuana trade.

A spokeswoman for the U.S. Attorney's Office for the Eastern District of Pennsylvania did not respond to a request for comment. A spokesman for the Philadelphia office of the Drug Enforcement Administration said his office had not yet received new guidance documents.

The pot business has since become a sophisticated, multimillion-dollar industry that helps fund schools, educational programs, and law enforcement. Eight states and Washington, D.C., have legalized marijuana for recreational use, with Vermont and New Hampshire expected to approve legalization in the coming weeks and Delaware also studying legalization. California's sales alone are projected to bring in $1 billion annually in tax revenue within several years.

Sessions and some law enforcement officials blame legalization for a number of problems. They say drug traffickers have taken advantage of lax marijuana laws to hide in plain sight, illegally growing and shipping the drug across state lines, where it can sell for much more.

Sessions' announcement was a win for pot opponents who had been urging the Department of Justice to take action.

"There is no more safe haven with regard to the federal government and marijuana, but it's also the beginning of the story and not the end," said Kevin Sabet, president and CEO of Smart Approaches to Marijuana, who was among several anti-marijuana advocates who met with Sessions last month. "This is a victory. It's going to dry up a lot of the institutional investment that has gone toward marijuana in the last five years."

Some officials in states that have legalized it for adult recreational use were furious.

Sen. Cory Gardner, a Colorado Republican, accused Sessions of flipflopping, tweeting that the action "directly contradicts what Attorney General Sessions told me prior to his confirmation. With no prior notice to Congress, the Justice Department has trampled on the will of the voters in CO and other states."

"I am prepared to take all steps necessary, including holding DOJ nominees, until the Attorney General lives up to the commitment he made to me prior to his confirmation," Gardner tweeted.

This article contains information from the Associated Press.