Hoping to regain momentum as two rival candidates creep closer in the polls, Vermont Sen. Bernie Sanders returned to his signature policy theme in a major speech Wednesday: a single-payer, "Medicare for All" health insurance system.

"The time is now to go forward. The time is now to expand Medicare to every man, woman, and child in this country," Sanders told supporters and reporters in Washington, D.C.

Sanders outlined in broad strokes how he'd implement Medicare for All: He'd lower the eligibility age from 65 to 55 in the first year of the new program, then to 45, then 35, then eventually to every adult.

Children, Sanders said, would be eligible for the insurance program in the first year of the transition.

Sanders also said he also wants to expand Medicare beyond its current benefits to include dental coverage as well.

"The desire to have teeth in your mouth is a health care issue," he said.

Sanders argues that universal, government-run health care would lower medical costs and eliminate insurance premiums, deductibles, and payments — but he also acknowledged his proposal would require tax increases.

Sanders mocked the idea of families celebrating the status-quo insurance costs that he has pledged to eliminate.

"Oh my God, dear, the insurance premium is here, what a wonderful day," he said. "Oh wow, let's celebrate."

The costs for a program like the one Sanders has outlined long have been a sticking point. Two years ago, California legislative analysts put the price tag of a potential single-payer health care system at $400 billion for California alone.

The bill in question died in California's Assembly, which is overwhelmingly Democratic.

Striving to stand out

The speech comes at a time when Sanders is facing increasing pressure from other Democrats in the top tier of polling and fundraising: most notably, Massachusetts Sen. Elizabeth Warren and California Sen. Kamala Harris.

While Sanders had long registered far above any other candidate but former Vice President Joe Biden, Harris and Warren have gained substantial ground in recent weeks.

Warren has narrowly jumped past Sanders into second place, behind Biden, in a handful of surveys, and raised more money than Sanders from individual contributions in the last quarter.

Sanders' campaign leaders say they're aware of the shifting dynamics but they're not panicking.

"I think it's more of the case that other people are gaining some attention and traction. They are new candidates in the race, and that is a credit to them," said campaign manager Faiz Shakir. "They're fresher to the scene for that reason, so you're seeing other candidates get a little more support, which is good. It's healthy. It's fine."

Still, Sanders has been reluctant to criticize Warren, Harris and other candidates who have embraced large planks from his progressive platform, even as he competes with them for support.

"Elizabeth [Warren] is a longtime friend of mine, she is a very good senator," Sanders recently told NPR. "Elizabeth's running her campaign. I'm running my campaign."

The hesitance is especially notable since Harris has repeatedly vacillated on her support for a core aspect of the Sanders Medicare for All plan she has co-sponsored in the Senate: the complete elimination of private health insurance, outside of supplementary plans.

In a CNN interview this week, Harris said it would likely take more than four years to fully transition from the current health care system to Medicare for All.

Harris also argued that preserving private health insurance ensures more coverage for more Americans without raising taxes on the middle class.

Sanders has acknowledged his health care proposals would require higher taxes — but argues it would also lower medical bills and eliminated insurance costs, making the increase worth it.

And while Warren laid out several detailed policy plans during the initial months of her presidential campaign, she too did not unequivocally back the full elimination of private health insurance until last month's debate.

Instead of pointing out those inconsistencies to progressives who may be migrating to support for Harris and Warren, Sanders has focused his fire on Biden, attacking what Sanders rejects as a "middle ground" approach to politics.

Biden's less radical outlook

In the days since Biden unveiled a health care plan centered around the existing Affordable Care Act, or Obamacare, and creating a public option government insurance plan, Sanders and his campaign have gone as far as comparing Biden's view on health care to President Trump's.

Earlier this week, Sanders' camp sent an email to reporters warning that an Obamacare-centered health insurance plan "leaves nearly 10 million people uninsured," and "leaves people at the whims of their employers."

That's despite the fact that Sanders helped lead the effort to save the Affordable Care Act in 2017 and 2018, when Republican majorities in the House and Senate tried and failed to repeal Obamacare.

"The Affordable Care Act took us a step forward," Sanders told NPR in 2017, even as he advocated for an eventual shift to a single-payer system. "It provided health insurance for over 20 million more Americans. That's no small thing. It did away with the obscenity of preexisting conditions and a number of other essential health care benefits that are now guaranteed to the American people. So it made some real change."

For his part, Biden has framed Medicare for All as a "risky" elimination of an Affordable Care Act that he argues is already here and working.

"I knew Republicans would do everything in their power to repeal Obamacare. They still are. But I'm surprised that so many Democrats are running on getting rid of it," Biden said in a campaign video posted this week.

"I understand the appeal of Medicare for All," Biden said. "But folks supporting it should be clear that it means getting rid of Obamacare, and I'm not for that."

Copyright NPR 2019.