Running a campaign is hard work. It is both time consuming and expensive. Knowing this, and before announcing his/her candidacy, and during the process to decide whether to run or not run, the Candidate must take a hard look at himself or herself. The Candidate must decide whether there are skeleton(s) in the closet that will affect the campaign. The Candidate's personal, financial and professional records must not present any questionable, lapses in judgment that will prove to be embarrassing during the campaign. The Candidate's general reputation in the community must be "good". A good campaign can be brought to an end by what is "in the closet" of a Candidate.
This does not mean a Candidate must be a perfect person to run; there may be matters of concern about the Candidate's past and Candidate still runs for public office. It simply means that anything in the Candidate's past that may potentially be a problem must be made known to the Candidate's key advisors and the Candidate's family before the decision to run is made. The Candidate's past misstep should not be a surprise (something learned from one other than the Candidate) to those closest to the Candidate.
If there is a reasonable explanation for the matter of concern and if disclosed to the public, the matter of concern will not become a distraction, dominating the campaign, a Candidate with a less than perfect past may run.
Further if the matter of concern is one that happened when the Candidate was of a youthful age (depending upon community norms one under the age of 25 could be considered youthful) the voting public will probably forgive the Candidate attributing the misstep to youthful indiscretion. This is particularly so if the Candidate has had no other missteps and the Candidate has been a good citizen in the community since having the misstep.
Whether a Candidate with a problem past should run a campaign is depended upon how well the Candidate is prepared to handle questions about the misstep ( this is the reason for discussing the misstep with close advisors so that the advisors can assist with preparing a response to questions about the misstep) and what the Candidate has done in the community since the misstep. The Candidate must be honest and forthright when speaking about the misstep. The Candidate must not offer any excuses for the misstep. The Candidate must be able to show that in spite of the misstep, the Candidate has moved beyond the misstep and become a positive contributing member of the community.
Of course, if the Candidate has multiple missteps, the voting public will probably be less likely to support the Candidate.