Where did you hear that?
Looking over the list of polls (link below), the only one that looked a bit worrisome was Baldwin tied with her opponent in Wisconsin, but that was on July 10 — four other polls (three of them more recent than that) show Baldwin rather comfortably ahead.
There’s a recent poll with Brown only up by 4 in Ohio — could that be it?
Since early this year, we’ve known that Gallego’s Arizona race would be quite close, and it likely will be, but polls show him with a small lead at this point, so that’s good.
(Maybe we should continue this discussion in the Senate thread?)