The evasion in the statement "Only a dishonest person would argue against the proposed penalties for theft" is best identified as a straw man argument.
This is because the statement misrepresents the position of those who argue against the penalties, implying that they are inherently dishonest, rather than addressing their actual reasons or arguments against the proposed penalties. By framing the opposition in such a way, it distracts from the real debate about the merits or drawbacks of the penalties themselves.