It's difficult to give specific advice without knowing the actual traffic level(1) and type of ads and placements(2) you have on your website but I'll make the assumption that those visitors don't record visits of extraordinary length resulting in at least several hundreds of thousands of pageviews/month.

In this case, your best bet would be to sell your ad space in a tenure model (per month, for example) as opposed to CPM or another, less advantageous pricing model. This would ensure you're covered for any traffic fluctuation, don't have to deal with monetizing remnant inventory, and usually translates in higher eCPMs overall.

Tip: offer campaign features not usually associated with smaller publishers, as a strategy to stand out. For the Politics vertical, I'd suggest looking into a guarantee that no competing campaigns would be displayed simultaneously (you can do so in pretty much any ad server out there).

(1) pageviews, ad impressions
(2) number of ad placements, sizes, location, type of ad creatives