Schlieffen believed that defending was usually better than attacking. Schlieffen said that a defender's men can ride trains to a place faster than an attacker's men can walk there. This meant that the defender would always have enough men to stop the attacker. Schlieffen also said that trenches, machine guns, and barbed wire would help the defender a lot. Schlieffen was right. In WWI, defense was always better until attackers used lots of artillery to help their infantry.