According to Jervis, the technical capabilities of a state and its geographical position are two essential factors in deciding whether offensive or defensive action is advantageous. He argues that at a strategic level, technical and geographical factors are of greater favor to the defender. For example, in the 19th century railway and roads construction were rapidly changing the composition of capabilities of states to attack or defend themselves from other states. Thus, considerable effort in diplomatic relations and intelligence were specifically focused on this issue.