You do your homework. What are this person's qualifications. What has this person achieved. What is this person's character. Is there anyone better qualified to do the job.
There were "conservatives" who did not support Gov. Romney because he was a Mormon (of course there were other reasons also) but there is no question that this country would have been much better off if he had won the last election.
LIBERAL
There were also conservatives who did not support Governor Romney because he is not a conservative. He would have been a better manager than Obama, without question, but the general direction of ever-growing government would not have altered, unless he completely changed. He was the PERFECT establishment candidate in every conceivable way, and ran a technically sound campaign. He won independents handily. He lost the election.