If I were a Republican, I wouldn't even want Ernst to win. She'll harm the party by being such an embarrassment way more than her individual vote will help.
One senator either way, even when "control" is at stake, means very little. The exact count only matters when one party is approaching 60, and that's pretty unlikely to happen either way in the next 6 years.
And yes, I would say the same thing in real life if the Democrats had nominated a liberal equivalent of her in one of the close races.
Nothing Ernst would do or say could possibly damage the GOP in any meaningful way. They already have Cruz/Bachmann/King/Gohmert/Stockman etc. etc. and are about to perform respectably in the midterms anyway.
