Yesterday, I related the results of a new CNN / ORC Poll that showed Hillary Clinton had retained her large lead over Bernie Sanders nationally. Now a second poll has been released that verifies that. It is the Monmouth University Poll -- done between October 15th and 18th of a random national sample of 340 registered Democrats, with a 5.3 point margin of error (see top charts).
This survey shows Hillary Clinton leading Bernie Sanders by 27 points. That's with Joe Biden being considered to be a candidate. If Biden is not considered, then Clinton's lead over Sanders jumps to 33 points.
Why does Clinton maintain such a large lead? We can get some clue to that by looking at the chart below (made from numbers in the CNN / ORC Poll). It shows that Democratic voters just trust Clinton more on the issues (although her edge on one issue, income inequality, is within the survey margin of error).
There's still a little over 3 months until the voting starts, and that could change. But it hasn't changed yet, and despite the best efforts of her opponents (and the media), there is no sign of her support "slipping".