Important follow-up story the next year. https://slate.com/news-and-politics/2016/05/the-koch-brother... “The Koch Brothers Were Supposed to Buy the 2016 Election: What happened?”

As the article notes, Trump (who was not Koch-backed) won with very little spending compared to his big-money backed conventional GOP opponents. They decided to step back and spend less in 2016 as a result, since they didn’t support either Trump or Hillary.