But swing voters often pick the winners in various elections, because they are the deciding factor. You don’t need that many of them, so there’s no way of telling for sure if they made a difference.
But bottom line: Republicans should pick Republicans.
“But swing voters often pick the winners in various elections.”
No. Swing voters pick the winner in every election.
As for your premise that Democrats crossed party lines to vote in GOP Primaries, you will need to show us one contested 2008 GOP Primary state where there was a historical shift of number of primary voters from the Democratic Primary to the GOP Primary.