The latest NBC News/Wall Street Journal poll has some encouraging news. The results show Joe Biden beating Trump nationally by a robust 52-43 margin and carrying the battleground states 50 percent to 42 percent.

When we go into the sub-tabs, though, we can perhaps see the limitations of a sample of only 900 voters. Biden only carries 84 percent of the black vote and leads in the suburbs by a modest 49 percent to 45 percent. Those numbers not only seem disturbingly low, they also appear incompatible with the overall result. Certainly, if Biden is doing this poorly with two of the key demographic strengths of the Democratic Party then we shouldn’t expect to see him romping to a nine-point national lead.

The poll has Trump carrying 57 percent of white voters who lack a college degree, and perhaps this is too low. If not, then I suspect Biden’s lead will grow because it’s doubtful that Trump will do substantially better with black voters than any recent Republican or that he’ll have a better go of it in the suburbs than in the country as a whole. Overall, this poll shows positive top-line numbers but an implausible lack of polarization in the electorate.

It’s easier to believe that Biden is doing better with independents than expected than it is to believe that Trump is making major inroads into the Democratic base.

So, while I don’t think the sub-tabs are a good reflection of the electorate, they seem more likely to be undercounting Biden’s vote than Trump’s. Current events certainly lead me to believe that Trump is in more danger of seeing erosion in his base than Biden, so perhaps Trump really is failing to dominate with non-college whites.

Given the unsettled state of everything, a poll issued in March isn’t of much use anyway, but at least there’s some good news for a change.