By Anthony Salvanto, Jennifer De Pinto, Sarah Dutton and Fred Backus

Hillary Clinton continues to lead Vermont Sen. Bernie Sanders by 20 points: She receives 52 percent of Democratic primary voters' support, while Sanders gets 32 percent. Just 2 percent support former Maryland Gov. Martin O'Malley.

Clinton leads among many voter groups - men, women, liberals, moderates, non-whites and voters over age 45. But Sanders performs better with voters under 45 and independents.

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Handling the Issues

Clinton has an advantage over Sanders on two important issues: more Democratic primary voters are very confident in Clinton's (81 percent) than in Sanders' (65 percent) ability to handle the economy and terrorism.

However, 25 percent are very confident in Sanders' ability to reduce income inequality, an issue he focuses on in his campaign, compared to 18 percent who are very confident in Clinton's ability on this issue.

Candidate Qualities

And nearly two-thirds of Democratic primary voters think Clinton has been specific when talking about how she would accomplish her goals. While that is more than say the same for Sanders, a majority -- 55 percent -- thinks he has done so, too.

Sixty-two percent of Democratic voters think that Sanders says what he believes, compared with 52 percent who think that Clinton does so.

When asked what candidate quality is most important to them in their choice of a candidate, Democratic primary voters choose bringing about change (25 percent), having the right experience (22 percent) and a strong leader (21 percent). Further down the list are caring about them (14 percent) and honesty (14 percent).

Expectations

Expectations that Clinton will be nominated this year run high. Nearly three in four Democratic primary voters expect Clinton to be the Democratic nominee.

Mind Made Up?

As the first nominating contests grow closer, Clinton's supporters are firmer in their choice (58 percent) than Bernie Sanders' supporters (47 percent).

This poll was conducted by telephone December 4-8, 2015 among a random sample of 1,275 adults nationwide, including 1,053 registered voters. Data collection was conducted on behalf of CBS News and the New York Times by SSRS of Media, PA. Phone numbers were dialed from samples of both standard land-line and cell phones.

The poll employed a random digit dial methodology. For the landline sample, a respondent was randomly selected from all adults in the household. For the cell sample, interviews were conducted with the person who answered the phone.

Interviews were conducted in English and Spanish using live interviewers.

The data have been weighted to reflect U.S. Census figures on demographic variables.

The error due to sampling for results based on the entire sample could be plus or minus three percentage points. The error for subgroups may be higher and is available by request. The margin of error includes the effects of standard weighting procedures which enlarge sampling error slightly.

The margin of error for the sample of 384 Democratic primary voters is 6 percentage points.

This poll release conforms to the Standards of Disclosure of the National Council on Public Polls.