Rep. Alexandria Ocasio-Cortez (D-N.Y.), one of Bernie Sanders’s most vocal and visible allies in his presidential campaign, said last week that Democrats may have to “compromise deeply” on the Vermont senator’s signature “Medicare for All” plan to get the legislation passed. Sanders, however, pushed back Tuesday, insisting his policy proposal is “already a compromise.”

Ocasio-Cortez, who endorsed Sanders in October, is a fervent proponent of Medicare for All, but in an interview with HuffPost’s Matt Fuller, she said she was realistic about the political process as well.

“A president can’t wave a magic wand and pass any legislation they want,” she said, adding that “the worst-case scenario” if Sanders is elected president is that Democrats “compromise deeply and we end up getting a public option.”

“Is that a nightmare? I don’t think so,” she added.

Under Sanders’s Medicare for All plan, all Americans would eventually get health insurance through the government’s Medicare program. A public option, on the other hand, would offer some Americans the opportunity to buy into government-run insurance plans.

In a follow-up tweet, Ocasio-Cortez said, “I think there’s a legitimate [conversation between] starting with what you want & starting w/ compromise.” But she added that she believes a “public option is worse” than Medicare for All, “so we should fight for” Medicare for All first.

Sanders was asked about Ocasio-Cortez’s comments at a CNN town hall in Las Vegas on Tuesday night.

“I love Rep. Alexandria Ocasio-Cortez. She has done more in her first year in Congress to transform politics, to get young people involved, than any freshman member of Congress that I can remember,” the Democratic presidential contender told moderator Anderson Cooper.

“But my view is that Medicare for All, the bill that we wrote, is in a sense already a compromise,” he said.

Notable: Asked by Anderson Cooper in a CNN town hall about @AOC's recent comments to HuffPo on health-care - she said a "worst-case scenario" would be compromising for a public option -- @BernieSanders says his Medicare for all plan is "already a compromise." — Sean Sullivan (@WaPoSean) February 19, 2020

Sanders added that his proposal includes a four-year transition period that would gradually lower the age for Medicare eligibility from 65 to 35.

“And then we cover everybody,” Sanders said. “What this means [is] … no more premiums, no more co-payments, no more deductibles, no more out-of-pocket expenses ― and we’re going to fund it publicly. For the average American, it will be a significant, significant reduction in his or her health care costs.”

Later at his own CNN town hall, Sanders’s presidential rival Pete Buttigieg took aim at Medicare for All.

“This is where I part ways with my friend Sen. Sanders,” said Buttigieg, who supports a public option health insurance plan. “He believes that we should require everybody to adopt that plan, whether they want to or not.”

But, he continued, “there’s a lot of folks here in the state of Nevada ... who negotiated for good private plans .... Who are we to tell them they have to give it up?”