It would have been more important to try to defeat people like McCain, Flake, and Murkowski. Defeating Lugar sent a message to the GOP. As well as Sanford winning. Even Collins seems scared of a primary.
Another problem is the dems winning close races in red states. The ND Dem Senator Heidi Heitkamp will be all for this amnesty. Even though it is against the interests of her state. Which means more Democrat and La Raza voters can vote for nationwide gun bans. Rick Berg would have more likely voted against the amnesty.
The senate is essential. Unfortunately, the concern trolls are already whining “what if we lose the House? boo hoo!”