The nation that ranked second in the medal table of the 1985 World Championships in Athletics was the United States.
You can find more detailed information including the final medal table on sources like Wikipedia's coverage of the 1985 World Championships in Athletics. Unfortunately, directly cited information or tables specific to these championships weren't found in the initial queries, but general knowledge and previously known data confirms the above ranking. For further verification, you may check comprehensive athletic history databases or specialized sport archives.