I didn't mention this in my previous post, but in addition to the aforementioned questions, NBC News and the Wall Street Journal asked respondents about the recent controversies over Bain Capital and Mitt Romney's tax returns to gage whether they affected support for the Republican nominee. Neither result was good. Here's the first question:

Has what you have seen, read, or heard about Mitt Romney's previous business experience managing a firm that specializes in buying, restructuring, and selling companies made you feel … more positive or more negative about him, not made much difference in your opinion or do you not know enough about this to have an opinion at this time?

Twenty-five percent said it made them feel more positive, 28 percent more negative, and 27 percent said it made no difference. When you remember that Romney has made this his chief qualification for the presidency, it speaks to the failure of his campaign to effectively rebut the charges. At best, Bain Capital is a non-factor for Romney, and for a significant number of people, it's a detriment.

The ongoing fight over his tax returns has done even more damage to the former Massachusetts governor. Here's the question:

Has what you have seen, read, or heard about Mitt Romney's tax returns and the percent he has paid in federal income taxes made you feel … more positive or more negative about him, not made much difference in your opinion or do you not know enough about this to have an opinion at this time?

Only 6 percent of respondents say that it has made a positive difference in their opinion of Romney. Thirty-six percent say that it has made a negative difference, and 41 percent say that it hasn't made much difference at all. Seventeen percent don't know either way. Romney's anger over the Obama campaign's decision to go after his tax returns makes more sense in this light; the controversy is doing real damage to his campaign, and more important, it has the potential to do more if Team Obama can return it to the forefront of the discussion.

I wouldn't bet against that possibility. As long as Romney refuses to release his returns, Obama can continue to hit him on the issue. Death by a thousand cuts is an exaggeration, but it's not far off from what might happen; Romney could become defined by the things he won't reveal, and gradually loses the trust of the public. His low favorability becomes a burden he can't lift, keeping him behind Obama through the fall, and into the election.