Captain America’s shield has always been his favorite weapon. Why Not? It can block anything from a solar system destroying Phoenix Blast to a direct hit from a planet busting strike. It works every time except for when it doesn’t. That being said, a superb defense does not always translate into a great offense and Ronan will easily be able to deal damage to the Captain eventually while Rogers doesn’t really have anything at his disposal to take care of the accuser. Ronan The Accuser wins.
Update Captain America’s Nova form definitely takes the win here.