Democracy requires transparency, openness and responsiveness to the people, but done correctly, it's not a problem that can't deal with terrorism; those who would terrorize America will find their hopes dashed against a pointed spear and an iron shield. Terrorism is one aspect of asymmetric warfare. It is conducted by weaker opponents against stronger ones, and the preferred tactic many pursue if they can't field an army on the field to take ground and defend it. The problem with almost every land campaign against the USA ends with the same outcome: opposite side can't mass their forces, so individually they become tempting targets. Meaning nobody can blitzkrieg the USA, while we can do that and more. It's simple, really: terrorism is here to stay.
A compromised communications system particularly within the military is one of the major vulnerabilities in a democratic society that expose it to terrorism. The government has to channel the right resources towards reducing these vulnerabilities to terrorist attacks