A response to Peter

I think the Senate has every right to study a nominee's ideology, at least with respect to this issue:
I believe that the Constituion, specifically the Bill of Rights, is an enumeration of specific rights that the state does not have, and, in essence, a statement that the guiding principle of American governance is not "majority rules", but "defense of the individual". The state, nor any of its agencies, cannot infringe on my rights to do a whole long list of things, regardless of the popularity or offensiveness of my viewpoint.

However, because the other two branches of government are populated with people who have their positions due to popularity contests (elections), their continuing power partially depends on succumbing to the will of the majority, regardless of how that affects individuals. Therefore, it is incumbent upon the judiciary to defend the rights of individuals, as spelled out in the constitution, or the document becomes meaningless. So, if a nominee's ideology is that governmental rights trump individual rights, or that our laws should be based on what's popular (say, Christian theology), or that their ideology unduly influences their ability to carry out the duties of their job (like, say, a pharmacist who refuses to fill prescriptions), then, while their academic and professional training may appear adequate, they are not suitable for that job.