I would like to bet on the mid-term elections in the USA. Are there any long-running legit prediction markets that are somewhat liquid where I can do this?

I haven't paid attention to the Bitcoin gambling space for a while, so I am out of touch with the scene. How can I vet the site that I bet on? There seem to be a few Bitcoin betting review sites, but they all have affiliate links, so it looks like they will shill for just about anyone that gives them an affiliate deal.