Read the passage below and answer the question. Woodrow Wilson... recognized that the Constitution is best understood not as a machine at all but as a living thing. What he did not add was that it's a living thing with no body or mind, no moving parts or organs or spirit separate from the bodies and minds and spirits of the people themselves, people whose constant vigilance—and I noticed when I was coming into the building [National Archives] that statement "Eternal vigilance is the price of liberty," appropriate to have on the archives – people whose constant vigilance is the lifeblood of Constitutional survival.

Explain in about 50 words what the passage means.