Naturally so, especially the longtime pols who had no problem supporting Menendez in 2018. They're going to have a hard time pretending to be shocked by this indictment, but they'll try.
But the truth is also that Menendez has been a bit of a ghost in New Jersey for a long time. There's not going to be, for example, a lot of pictures of candidates shaking his hand or quotes of them vocally supporting him.
And if he (hopefully) resigns soon, it'll just fade from relevance as the news cycle turns, except in the races when someone is actually hypothetically best buddies with the senator.