Of course.
Whoooda thunk?? Another criminal hiding behind the Fifth.
Witnesses don’t get to plead the 5th. You have to be in line for being a suspect at least. Fusion GPS is not going to be prosecuted for anything. All they did was take money and deliver a product. Slimy. Evil. But not criminal. Now Nellie Ohr may want to take the 5th, but Simpson doesn’t seem to be under criminal suspicion of anything that I can see.
This is not a criminal case so the 5th Amendment does not apply. Congress can compel him to testify.
It’s his right to plead the 5th.
But drag his a$$ in the committee room to do it.
Make him repeat his 5th statement over and over again.