There is a high likelihood that this is declared a mistrial, and Menendez gets a new trial. How fucked is he? I need to bring that 10 down. The evidence against him is really strong, but juries are really stupid. Why? A jury of 12 people is a group of 12 people too stupid to get out of jury duty (origin: unknown). In the case of a high-profile political case, they are people who don't know shit about shit.
That will be true for the next jury too. Let's bring that 10 down to a 7. That puts him a notch below Manafort's current 8.
The important thing politically, though, is that the seat won't be vacated for Christie to appoint a replacement. Even if this goes to a new trial, and Menendez is convicted, a Democrat will appoint Menendez's replacement.