The Senate, like its counterpart the House of Representatives, has the mandate and the power to conduct hearings and investigations, and to invite anyone to these hearings and investigations. The underlying reason for these hearings and investigations, and for inviting anyone thereto, is so it can be aided in the pursuit of its primary duty and obligation, which is legislation.
Take note of the operative terms underlying all of these activities because they are critical in understanding their very nature. These terms are "invitation" and "in aid of legislation." When someone is "invited" to these hearings and investigations, it is because they are considered "guests or resource persons." They are not regarded as suspects. There are no suspects in a hearing or invitation "in aid of legislation." That only happens in court in case of litigation.
When a person is invited as a guest or resource person to a Senate hearing or investigation, it is because the Senate values his inputs and believes that acquiring such inputs freely and honestly helps it in its primary task of legislation. In pursuing that objective, it is essential for the Senate to respect what the guest or resource person has to say, regardless of whether it believes what is being said or not.
The Senate cannot argue with a guest or resource person because that defeats the very purpose of his coming. It may not like what the guest or resource person has to say but it has to take his word for it, otherwise why invite him in the first place if it only ends up arguing with him. If a lawyer, whether of the prosecution or of the defense, is not allowed to argue with a witness in a court of law, all the more that senators must not argue with a guest or resource person in a hearing or investigation which is just in aid of legislation.
Even more important, senators must not be allowed to harass, scold, intimidate, browbeat or threaten guests and resource persons, or pass judgment on their innocence or guilt because they are not there as suspects in a crime even if the senators may think so. Parliamentary immunity is not a license to slander anyone or strip him of his dignity.
In a Senate hearing or inquiry, where a guest or resource person is invited for what he has to say and not to answer for any crime, the guest or resource person is king and must be accorded the highest respect. It is not the other way around. He should be addressed as sir and should not be addressing senators as your honors because they are not judges and the Senate is not a court.
A guest or resource person, especially if law-abiding and with no criminal record and is a conscientious taxpayer, is the boss of the senators and should be regarded accordingly. From his taxes come the salaries and the perks of the senators. From his vote comes the mandate that gives senators their sense of importance and power. What scorn or disdain senators may have for a particular guest or resource person must be restrained and not taint the dignity of the proceedings.