I think a detailed investigation should be SOP for all Politicians
Conducted by Democrats? Conducted by whom?I will say that some purple state(s) should IMHO allow suits against allowing Electors pledged to candidates to be placed on the ballot in presidential election. Such suits should be limited to transparent constitutional ineligibility - e.g., “the candidate is under the age of 35,” or “the candidate violated the Emoluments Clause as Secretary of State by raising money to be under the candidate’s control from foreign government officials.”
Also, there could be a question of neurological fitness; the public has a right to know if a quantifiable neurological issue affects a candidate for POTUS. Can Hillary walk freely up and down stairs now? It appeared that she couldn’t, during the ’16 campaign. FDR functioned in a wheelchair while POTUS, and that was not debilitating to the country - but there are neurological conditions which would be far more problematic.
I would not, however, favor requiring disclosure of IRS data - that’s intrusive and could produce more heat than light. But I would look with favor on financial disclosure of foreign sources of income.