Resolves to the earliest time at which 538 shows an even or net negative approval rating for Donald Trump in his second term: https://projects.fivethirtyeight.com/polls/approval/donald-trump/

As of 2/20, here is his approval rating:

Note: I'm not 100% sure how it displays if the net approval is rounded to 0.0. If it shows anything that indicates which way it leans, I will consider the approval rating to be positive or negative based on that. For example, if we have Approve 47.6%, Disapprove 47.5%, but the net approval is 0.0%, I will know it was rounded down, so I will still consider it positive, and thus the streams will not have crossed yet. Likewise, if it says Approve +0.0 or still shows a green box around the net approval rating, I will know that it's still slightly positive. I'm pretty sure it doesn't do this, and will show a grey box with no plus or minus sign, though - in this case, I will consider the streams to have crossed unless there's some other piece of information indicating that they haven't (like the example where the non-net approval and disapproval ratings are rounded such that you can tell which one is higher).