Originally Posted by MSPeconomist

I don't think this is true necessarily. For overnights along the way in Europe, for example at AMS, I'm usually able to either retrieve the bag or check it through, although this requires paying attention at check in.

However, officially I believe there's now a rule that for less than four hours, the bag is checked through, for 4-8 hours, it's your option, and over 8 hours one must retrieve and then recheck the bag within four hours of departure.

An additional complication is that you pick up the bag to walk it through customs when you enter the USA. If they're paying attention when you try to recheck the bag, DL could refuse to accept it even if it's been tagged to be checked through. However, YMMV and I'm not sure the bag handling employees would notice.

BTW, using multicity to book should result in a single ticket (unless there are too many segments) and a single itinerary.