If the Senator from the home state of the letter writer does not serve on the Committee, the Senator passes along the letter to the Committee. This is a routine process for all positions requiring Senate confirmation. Not all citizen involvement is screened or suppressed on a partisan basis by the Senators. Bi-partisan cooperation is, in fact, more common than most people are willing to admit; a Senator from a solid Blue state for example, may be willing to trade their vote across the isle for federal judges in Red states to gain support for a nominee more favorable to them in their home Blue state.
Occasionally Senators may take interest in a letter, and ask for a sworn statement; a controversial letter may escalate up to a request to testify or [[subpoena]]. It is not uncommon at all for partisans to impugn a nominee's character, especially if a personsl relationship existed. It was at this step in the [[Anita Hill]], [[Blasey Ford]], and other cases related to Kavanaugh, Democrat staffers illegally leaked the unvetted information, putting public pressure on the letter writer to make sworn statements, and even testify. A person of some status, a college professor for example (as Anita Hill and Blasey Ford are), then may feel compelled to give questionable or even false testimony in an effort to mitigate damage to their reputation, having no idea at the start of the process they may be thrust into the limelight against their will.
==Blasey Ford/Feinstein allegation==