Thumbs Down to Carl Thomas and Bob Collins, both Republican candidates in last month’s Dallas County sheriffs election, for helping turn the already controversial race into a mudslinging contest. The two continually harped on the 1983 drunken-driving trial of incumbent candidate Sheriff Don Byrd instead of doing as voters asked and focusing on their own past merits as employees of the sheriff’s department. Both Thomas and Collins seem to have forgotten that Byrd was acquitted of the charges.