John Kerry is married to Teresa Heinz. Yes, the same Heinz family that makes the famous ketchup and (for our UK readers) the baked beans. The Heinz company has been making these pickle pins for over a hundred years. According to the Wikipedia, over a 100 million of them have been produced.
The main point here is that "pickle" might be a reference to John Kerry or his wife ("follow the wives"), especially since the last few crumbs have been about Iran.