Trump heads into the Republican convention with a 27 percent positive/60 percent negative score (-33) - remaining the most unpopular presumptive presidential nominee in the history of the NBC/WSJ poll.
But he's followed closely by Clinton's 34 percent positive/56 percent negative score (-22).
"Let me summarize the poll into four little words: 'They hate them both,'" says Democratic pollster Fred Yang of Hart Research Associates.
Trump also leads a fractured Republican Party: Only 38 percent of GOP voters in the poll are satisfied with Trump as their nominee, versus 54 percent of Democrats who are satisfied with Clinton.
What's more, a combined 85 percent of all voters - including 78 percent of Republicans - say the GOP is not that unified or only somewhat unified. That's compared with 48 percent of all voters (and 40 percent of Democrats) who say that about the Democratic Party.
Overall, the GOP has a 27 percent positive/51percent negative score (-24) in the poll, while the Democratic Party is at 39 percent positive/41 percent negative (-2). It's the first time in the history of the NBC/WSJ poll that both parties have been underwater going into the conventions.
As for Clinton and her own convention in Philadelphia that begins a week from Monday, the poll shows that the email controversy has taken a toll on her candidacy.
Fifty-five percent of all voters say her use of a private email server is important to their vote - up from 42 percent who said this in late Oct. 2015 after her testimony before the House Benghazi Committee.
In addition, half of voters - 50 percent - say she doesn't have the right judgment to make a good president based upon what they know about the FBI investigation into her email practices, versus 33 percent who say she has the right judgment.
"The questions about Mrs. Clinton's character and honesty are important obstacles, and the decision by the FBI so far hasn't ended the issue for the public," adds Yang, the Democratic pollster.
Still, more voters say that Clinton has the right judgment to be president (37 percent) than Trump does (25 percent), although a third (33 percent) say neither has the right judgment.
Also, a plurality of voters (43 percent) believe the FBI investigation was unfair and too partisan, versus 37 percent who say it was fair and impartial.
Another weakness Clinton has heading into her convention is the country's desire for change.
In the poll, 56 percent of voters prefer a presidential candidate who will bring major changes to the government, even if they're unpredictable. By contrast, 41 percent want a steady approach, even if it means fewer changes.