They don't operate that many flights to the US in the first place, and they are succsesful and long-established at all thier 8 North American destinations. What I could see happening:
1) Cutting one of the two-daily JFK-FCO flights
2) Maybe going back to the old ways at MIA; instead of the daily MD-11 to MXP, they could revert to the 5x weekly 742 to MXP (MoWeFr) and FCO (TuTh)
3) Reduce frequencies on FCO-YYZ
4) Reduce frequenices on MXP-BOS
5) Delay ATL flights
They have not added a US destiantion, I think, since MIA, which was added in 1990, and they operate Alitalia TEAM flights to cities like MIA, LAX, and SFO, which allows them to operate lower-yield routes while still making a profit.