A majority of states now allow residents to use compounds from low-THC cannabis as medicine, but growing the plants remains a federal crime and in some states parents of epileptic children risk losing them by using the non-intoxicating treatment.

Republican members of Congress, inspired by stories from desperate parents who say use of low-THC, high-cannabidiol (CBD) cannabis saved their children, are taking the fight for legalization from statehouses to the U.S. Capitol.

The leaders of the effort, Reps. Scott Perry, R-Pa., and Robert Dold, R-Ill., aren’t among the usual suspects for marijuana reform legislation, and they see the bill as something that could be an easy, limited fix that can quickly pass in Congress.

“This is becoming mainstream,” Perry said at a Wednesday press conference. “It’s not some fringe, crazy idea.”

Medical marijuana is overwhelmingly popular among Americans and is legal under local law in 23 states and the nation’s capital to treat certain conditions. Thirteen other states allow cannabidiol from low-THC cannabis for medical treatment.

Federal law makes growing or possessing cannabis for purposes outside limited research illegal, and doctors cannot prescribe it because it’s a Schedule I drug under the Controlled Substances Act, meaning it is considered to have no accepted medical value and a high potential for abuse.

In a sign of softening attitudes, the House of Representatives voted 219-189 last year to ban federal prosecutors and anti-drug agents from spending funds to undercut state medical marijuana laws – though that ban, incorporated in a spending deal that became law, did not end existing prosecutions, change the underlying law or extend any protection to residents of states without such laws.

This year, momentum toward reforming federal law is seen in a major reform package that would lower marijuana’s federal classification to Schedule II, allowing for greater research and opening the door to its legal use as medicine. A Senate bill was introduced in March by Sens. Rand Paul, R-Ky., Cory Booker, D-N.J., and Kirsten Gillibrand, D-N.Y. A House version has 14 co-sponsors.

On Wednesday, a dozen members of Congress – six of them Republicans – reintroduced legislation that would immunize from federal prosecution anyone complying with state marijuana laws. Almost simultaneously, however, the GOP-led House appropriations committee rejected an amendment from Rep. Sam Farr, D-Calif., to allow Veterans Health Administration doctors to recommend medical pot.

The low-THC bill from Perry and Dold, the Charlotte's Web Medical Access Act, was introduced last month and would remove cannabidiol and cannabis plants with less than 0.3 percent THC from the federal definition of marijuana, legalizing production of hemp – used for rope, clothing, food and oil – and allowing CBD-loaded “hemp oil” to be legally used throughout the country.

Fourteen Democrats and 13 Republicans have signed onto the bill, which would set a lower THC limit than allowed by most state laws. Rep. Paul Ryan of Wisconsin, the Republican vice presidential candidate in 2012, is among its co-sponsors.

"It's a narrow exception that is worthy of being granted," Ryan told the Racine Journal Times.

The bill would not legalize all medical marijuana use and would not affect higher-THC marijuana’s classification as a Schedule I drug.

Spokesmen for two leading opponents of loosening marijuana laws, Reps. John Fleming, R-La., and Andy Harris, R-Md., did not respond to requests for comment on the bill.

Rare treatment-resistant forms of epilepsy are the most well-known conditions that appear to be well-treated by CBD. Politically active parents of children affected say they have seen a dramatic reduction in the number of debilitating, development-stunting seizures.

“This is not something I ever dreamed I’d be a champion of,” Perry said at the press conference, flanked by three mothers who said they are politically conservative and were at first hesitant to embrace the cannabis-derived treatment.

Perry, who’s not committed to legalizing marijuana for broader medical use, said hemp oil has “no known side effects” – a significant contrast to some anti-seizure medicines that parents say are less effective – and that the bill is needed so “individuals and states don’t have to flout federal law.”

The Obama administration can make the change administratively, and Perry expressed optimism that the resignation of anti-medical marijuana DEA Administrator Michele Leonhart may open the door for that to happen.

“When there’s a change in individuals there can be a change in mindset,” he said, adding he plans to focus on passing the bill because “these children need it now and they can’t wait for the bureaucracy.”

Coalition for Access Now founder Paige Figi, whose daughter Charlotte is the namesake of the bill and a strain of low-THC, high-CBD cannabis, said she watched her daughter confined to a wheelchair “dying” from seizures from Dravet syndrome before trying cannabis.

Now, she said, Charlotte has seen a 90 percent reduction in seizures, and is in a dance class and learning to ride horses in Colorado.

“This is life or death,” she said. “We want to get this done very, very quickly. … We’ve reached a tipping point with the state bills, it’s time for the federal government.”

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A self-described refugee, Liz Gorman, said at the event she relocated to Colorado with her young daughter and is forced to live apart from her husband, who is in the military in North Carolina.

“I don’t think people realize how many of us there are,” she said. “Hundreds of families have moved.”

Gorman said she allowed surgery to separate the hemispheres of her daughter’s brain and signed a form consenting to medication that could have caused the girl's bone marrow to fail – to no avail – before trying CBD, which she credits with a dramatic reduction in seizures.

“There is no legitimate reason we should not all have access,” she said. “It’s not very American for us to have to go live in very small, specific states.”

Lisa Smith of Virginia tearfully told how her daughter’s Dravet syndrome worsened over the years, causing about 300 seizures in 2012 before escalating to more than 1,000 last year.

Smith said it was impossible for her small business-owning family to move, and the family waited for Virginia to pass a CBD bill before beginning treatment. She's been using CBD for about a month, gradually increasing the dosage, and says her daughter is better able to stay awake and already has seen a 30-40 percent reduction in seizures.