Sources involved with Brett Kavanaugh's confirmation are nervous going into today's 10:30 a.m. test vote.

Four senators are undecideds: Jeff Flake (R-Ariz.), Susan Collins (R-Maine), Lisa Murkowski (R-Alaska) and Joe Manchin (D-W.Va.).

A senior source involved in the process told me fairly late last night:

"We’re going into this vote and we don’t have 50 right now."

and we don’t have 50 right now." "There’s been a lot of work that was done today, by members wading through this material. I don’t want to put my thumb on the scale. Things keep moving — so much, it feels like we’re walking on quicksand. So I don’t even want to say confidence or not confidence."

"Sometimes you just have to vote," the source added. "But what if ... something f—g happens in the morning? This whole process has just been ... so much drama, so many balls coming out at the last minute."

At 7:30 last night, Kavanaugh gave his final argument in a Wall Street Journal op-ed, "I Am an Independent, Impartial Judge: Yes, I was emotional last Thursday. I hope everyone can understand I was there as a son, husband and dad."