Trump has ordered another FBI probe of Kavanaugh, the man's seventh of its kind, which will last less than a week. Though it's very unlikely that they'll find anything (as they found nothing the first six times), it's a major concession to the Democrats, who'll likely just vote unanimously against Kavanaugh anyways, and, more importantly, to "moderate" Republicans like Jeff Flake.
The GOP controls 51 out of 100 seats in the Senate. If one Republican defects, then it'll be 50-50, and Kavanaugh will be confirmed by Vice-President Mike Pence's tie-breaking vote. If two Republicans defect, then Kavanaugh will not be getting his seat.