I’m against “fusion” the way it has been practiced as a sort of “sore loser clause” here is Delaware. However, there is a case for fusion. And hat case is made well in this Reason magazine article.
If you don’t have time to read the whole thing – read this next sentence.
Rudy Guliani won his race for Mayor of New York City because he ran as the Republican candidate and the Liberal Party candidate at the same time.