Please can someone help me understand the references to coattails and coatanchor in the following sentence (from an article published in July 1996)? They don’t seem to be part of the UK’s political lexicon – are they commonly used in the political arena in the USA?

“No matter how big Mr. Clinton's landslide may turn out to be, he has few true believers, and therefore has no coattails with which to drag in a Democratic Congress. … Mr. Dole doesn't have coattails, either; however, he has a coatanchor, and his submergence alone may be enough to sink the Republican Congress.”

I have read this whole article but am still puzzled and although I have a guess, it doesn’t seem to fit into the context of the article. I can see that people can be swept along and benefit by clinging to Clinton’s or Dole’s coattails, but if this is the reference then I can’t see why a lack of ‘true believers’ means that they wouldn’t have any coattails and the reference to a coatanchor leaves me baffled!