Originally Posted by GUWonder

US-CPH-STR does not involve a passenger/cabin baggage security rescreening at CPH.

You will have to do Schengen entry passport control at CPH, but you don’t have to clear a passenger security screening checkpoint at CPH on this kind of itinerary since US origin flights are considered sterile under the one-stop security agreement applicable at CPH.

At times 45 minutes can be tight when doing IAD-CPH-onward Schengen flight, but more often than not it should be do-able — even more reliably do-able if you have luggage already checked in for your final destination since then they are more likely to wait a bit for late arriving passengers than deal with offloading checked-in luggage.