Voters rated Sen. Bernie Sanders (I-Vt.) the most honest of the Democratic presidential candidates when it comes to how their health care plans would affect individuals' costs.

The Morning Consult poll finds that 49 percent of all voters rate Sanders as honest on the question, compared to 20 percent who don't know and 31 percent who say he's dishonest.

In comparison, former Vice President Joe Biden got a rating of 41 percent honest to 38 percent dishonest, Sen. Elizabeth Warren (D-Mass.) was 36 percent honest to 37 percent dishonest and South Bend, Ind., Mayor Pete Buttigieg (D) was 30 percent honest to 26 percent dishonest.

As the debate over "Medicare for All" rages in the primary, Sanders has been upfront about the fact that taxes will have to go up for the middle class to pay for his plan, but he argues middle-class people will save money overall once the elimination of premiums and deductibles is factored in.

Warren, meanwhile, has taken heat for declining to directly answer the middle-class tax question. She has now said she will soon release a plan for how she will pay for Medicare for All.

All of the candidates rate higher among only Democratic voters, but Sanders still comes out on top on honesty, at 75 percent for Sanders, 67 percent for Biden, 62 percent for Warren and 51 percent for Buttigieg.

The poll also had a warning sign for Medicare for All. It found that just 31 percent of voters would support a plan "that would require the middle class to pay higher taxes, where the increased taxes were offset by overall savings on individual health care costs."

Fifty-one percent of voters were opposed to such a plan.