There was an earlier thread (closed down) on this cocktail that used bourbon. I substituted with rye and made a few other modifications:

3 cl WT 101 Rye
2 cl Campari
2 cl Cinzano sweet vermouth
1 dash Fee Brothers orange bitters

- fill cocktail shaker 1/3 full with ice
- add spirits and bitters
- stir for 30 seconds
- strain into chilled cocktail glass with marachino cherry & orange twist

Nice while grillin' on the back porch - next time I might drop the vermouth just a bit.