Teaching husband that spanking isn't the answer to everything?

My husband and I have 3 sons (ages 8, 7, and 4). We've always had relatively different parenting styles but spanking is one aspect of discipline that we absolutely cannot agree on. It's not that I don't think spanking is appropriate in some situations but my husband thinks it's appropriate in every situation. I have talked with him about trying things like warnings or timeout before spanking them but he has told me he sees no reason to use alternative methods of discipline when spanking is working "perfectly fine". It's not that non-physical methods of discipline don't work on our kids-he just doesn't feel the use in giving them a warning or putting them in timeout 2 times when he can just spank them once and not have to deal with it again. He said "the boys will behave themselves and they will listen to me the first time and if spanking is what gets that message across, then that's what I will continue to use". It's not that I'm asking him to completely stop spanking our kids-I just want him to at least try methods other than his hands to teach right from wrong. Is that too much to ask?