One of the factors behind Republican victories across the country was the party's success in excluding candidates who were over the top (e.g., in 2012, the candidates from Missouri [Akin] and Indiana [Mourdock]). This year they did a better job of vetting.

According to the NYTimes: "Republicans’ impressive showing Tuesday night — marking the first time the party will have a majority in both the House and Senate since 2006 — was the result of methodical plotting, careful candidate vetting and abundant preparation to ensure that the party’s candidates would avoid repeating the same devastating mistakes that cost them dearly in 2010 and 2012."

Looking ahead, what would the Democrats have to do to exclude equivalent over-the-top candidates from the 2016 primaries.