"In my experience of these things, parties which shout about dirty tricks and the like tend to do so because they fear a direct hit in some vulnerable part of their political anatomy"

This quote by Peter Mandelson recommends that when political parties accuse their opponents of using cheats, it is frequently due to the fact that they are fretted about being exposed for something they have actually done wrong. In other words, they are attempting to deflect attention far from their own misbehaviours and onto their opponents. This is a common tactic in politics, and it is typically utilized to try and discredit the opposition. Mandelson's quote implies that when parties accuse each other of utilizing cheats, it is often due to the fact that they are attempting to secure themselves from being exposed for something they have actually done incorrect. This is a pointer that in politics, it is necessary to be knowledgeable about the strategies that are being used by both sides.