It may be a winning ticket in the battle for the Democratic presidential nomination, but two new polls indicate "Medicare-for-all" is far from the right prescription in the general election race for the White House.

Nearly two-thirds of Democratic primary voters questioned in a new NBC News/Wall Street Journal national poll say they support a government-run single-payer Medicare-for-all style system that would replace existing private insurance. That plan is championed by Sens. Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont, the two progressive standard-bearers in the record-setting field of Democratic White House hopefuls.

WHAT THE LATEST FOX NEWS POLL SAYS ABOUT MEDICARE BUY-INS AND MEDICARE FOR ALL

But among all voters, support for such a plan plunges to just 41 percent. About 56 percent of registered voters oppose a "Medicare-for-all" plan that replaces private insurance.

The poll, released Sunday, indicates that what two-thirds of all voters do like is allowing a Medicare buy-in for those under 65 years old. That’s in line with the public option being pitched by former Vice President Joe Biden. Currently, the taxpayer-funded program covers Americans 65 and older.

The latest Fox News national poll also points to the popularity of the Medicare buy-in plan, with 83 percent of Democratic primary voters saying they favor the plan, which would allow individuals to buy into the government-run system. Even 51 percent of Republicans agree.

Among all voters, 68 percent support a buy-in system. But support for a "Medicare-for-all" plan that replaces private insurance nosedives to 46 percent among all voters in the Fox News poll, which was released last week. Sen. Kamala Harris of California also supports Medicare-for-all, albeit with a role for private insurers.

Health care has been a leading concern among Democratic primary voters, with the issue topping the past two primary debates.

READ THE FULL RESULTS OF THE LATEST FOX NEWS POLL

The NBC/WSJ poll was conducted Sept. 13-16, with 900 registered voters nationwide questioned by live telephone operators. The survey’s sampling error is 3.27 percentage points for all registered voters and 4.36 percentage points for Democratic primary voters.

The Fox News Poll was conducted Sept. 15-17, with 1,008 registered voters nationwide questioned by live telephone operators. The survey’s sampling error is 3 percentage points for all registered voters and 4.5 percentage points for Democratic primary voters.