I actually haven't seen all that much evidence that the Democrats as a whole are fighting him. Certain interests no doubt are, no surprise. You forget, the Democrats aren't like the GOP, they don't act as a bloc in most instances. I've not seen any wholesale move to oppose Roberts. Looks to me like standard going through the motions to see if anything pops up. There is less public record, so it means they have to do more digging to gauge him.