If it's OK to talk about Romney's dog in the 80s, why isn't it OK to talk about Clinton's girlfriend in the 90s?
Both tactics are stupid. The only reason the poser Rand Paul brought up Lewinsky is because Bill Clinton is coming to Kentucky to stump for Democratic candidates, and Paul is afraid of Bubba's fundraising power. So following the modern day GOP template, instead of winning with superior ideas, Paul went into the gutter.
Clinton has to come to Kentucky because Obama is too unpopular.
Your attempt to use a tu quoque fallacy to justify Rand Paul's strategy is indicative of the faux Right's inability to be the better man.