A survey conducted by Morning Consult shows Sen. Dean Heller, widely seen as the most vulnerable GOP incumbent, saw a slight uptick in his poll numbers during the last quarter of 2017.

The poll showed Heller at 41-39 (approval/disapproval), which is far from robust but, as the estimable expert Harry Enten pointed out, two percentage points better than the previous quarter.

These are not good numbers, but we don't know yet the full impact of the tax bill or other issues that may arise this year. I asked for the crosstabs, and they are interesting:

Among 699 GOP voters (MoE +/-3.7 percent): 57 percent approve, 29 percent disapprove and 13 percent don't know or have no opinion

Among 762 independent voters (MoE +/- 3.5 percent): 36 percent approve, 37 percent disapprove and 28 percent don't know or have no opinion

Among 692 Democratic voters (MoE +/- 3.7 percent): 29 percent approve, 52 percent disapprove and 19 percent don't know or have no opinion

Those numbers could be a lot worse, I suppose, with all caveats about all polls that they are snapshots in time, and this one covered a three-month period last year. (Morning Consult showed Hillary Clinton winning the popular vote by very close to the margin she won by in 2016.)

If Heller's numbers with the GOP are 2-to-1, he could survive that primary with Danny Tarkanian, although the turnout will be quite low, so these numbers may not apply. And if he can remain even among indies, he has a chance against Rep. Jacky Rosen.

Then again, it's Jan. 24.

(By the way, Catherine Cortez Masto's numbers are 45-31).