I think you are right and that abortion is a key issue. The problem is almost certainly in the delivery of the message. It is possible to be adamant in holding to a position without being a scold or sounding strident. Certainly within the party people need to respect and support one another’s positions if these also correspond to and give support to the core principles of the Republican Party overall.
Abortion is a state issue. It should not be dealt with at the federal level. This is just one example of how the Republican party has lost it’s “small-government” way.
Same with flag burning and gay marriage. They are local issues, for pete’s sake!
If California wants to abort itself out of existance... GOOD! That leaves all that room and resources to us who value life.