WASHINGTON —  President Obama and a key Senate Democrat said Friday they were willing to consider relaxing federal enforcement of the laws against marijuana for those who possess small amounts of the drug.

They were reacting to new voter-approved laws in Washington and Colorado that permit recreational users to have an ounce of marijuana at home. In addition, California and 17 other states allow the medical use of marijuana.

Despite this state-by-state move toward limited legalization, federal law still classifies marijuana as a highly dangerous drug and makes it a crime to sell or possess even tiny amounts.

"So what we're going to need to have is a conversation about, 'How do you reconcile a federal law that still says marijuana is a federal offense and state laws that it's legal?'" Obama told ABC News in an interview with  Barbara Walters .

The president said he was not ready "at this point" to support widespread legalization of marijuana, but added: "It would not make sense for us to see a top priority as going after recreational users in states that have determined it's legal.... We've got bigger fish to fry."

Sen.  Patrick J. Leahy (D-Vt.), chairman of the Judiciary Committee, said his panel would consider legislation early next year that could ease federal law for marijuana possession.

"One option would be to amend the Federal Controlled Substances Act to allow possession of up to one ounce of marijuana, at least in jurisdictions where it is legal under state law," Leahy said in a letter to R.  Gil Kerlikowske , director of the  Office of National Drug Control Policy .

Leahy asked Kerlikowske, the administration's so-called drug czar, "what assurance can and will the administration give to state officials involved in the licensing of marijuana retailers that they will not face federal criminal penalties for carrying out duties assigned to them under state law?"

Leahy said Obama's comments "reflect common sense. In a time of tight budget constraints, I want law enforcement to focus on violent crime. But now that we have a gap between federal and state laws on marijuana, we need more information and a wider discussion about where our priorities should be."

Critics of the federal drug laws saw the comments from Obama and Leahy as a sign that Washington's rigid opposition to marijuana may be ending.

"It's a tentative step in the right direction," Ethan Nadelmann, executive director of the Drug Policy Alliance, said of Obama's statement. "He said we need a 'conversation,' and that's very promising. This sounds a lot like what he said about gay marriage a couple of years ago."

Nadelmann said he would watch to see whether federal law enforcement officials at the  Justice Department will insist on an aggressive anti-marijuana policy, despite the milder words from the president and Atty. Gen. Eric H. Holder Jr.

Recent polls have shown the American public is about evenly split on whether personal use of small amounts of marijuana should be legalized. The initiatives to legalize recreational use of marijuana in Washington and Colorado easily won passage Nov. 6.

Steve DeAngelo, executive director of Harborside Health Center in Oakland, said he hoped Obama's comments would prompt Justice Department prosecutors in California to cease a crackdown on the medical cannabis industry that threatens to close his shops.

The U.S. attorney in San Francisco filed a lawsuit in July to seize Harborside's two properties, even though its main dispensary is licensed and regulated by the city of Oakland and seen by many as a model of the industry. A hearing in federal court next Thursday may determine whether the dispensary must close its doors.

"It would be a tragedy if the leading example of responsible and legally compliant medical cannabis distribution is shut down next week on the verge of a change in federal policy," DeAngelo said. "The word ironic doesn't just quite have enough bitterness in it."

In the past, the Obama administration has sent conflicting messages on  medical marijuana . Soon after taking office, the president and the attorney general pledged to pull back from the  George W. Bush administration's policy of using federal agents to shut down dispensaries in California and other states where medical marijuana is legal. But U.S. prosecutors there have continued to take aggressive action against those who sell large quantities of marijuana.

Obama said he has a duty to follow the law as it now exists. "This is a tough problem because  Congress has not yet changed the law," he told ABC. "I head up the executive branch. We're supposed to be carrying out the laws."

Tom Angell, chairman of the Marijuana Majority, said Obama could do more. The executive branch could take action to change the classification of marijuana as a dangerous drug.

"The president should lead on this issue instead of deferring to Congress," Angell said.

david.savage@latimes.com

Staff writers  Kim Murphy in Seattle and  Joe Mozingo in Los Angeles contributed to this report.