"As the life of the nation changes so must the interpretation of the document which contains it change, by a nice adjustment, determined not by the original intention of those who drew the paper, but by the exigencies and the new aspects of life itself." Woodrow Wilson wrote this in his book "Constitutional Government," and this idea, that of the "living Constitution," is likely Wilson's longest lasting legacy to the American people. Whether you approve or disapprove of the thought, the idea that the U.S. government should not be limited by the original intent of the writers of the U.S. Constitution is an idea of enormous significance, an idea that allowed a great expansion of federal that power that we live under, for better or worse, today.
Where did Wilson get an idea like this? Wilson believed that both the conditions, and the nature, of man was improving with time. He was our first president to publicly deride the Constitution - he rejected the idea contained within it that human nature was fixed, and that as a result there were certain universal political principles that should apply at all times. "No doubt a lot of nonsense has been talked about the inalienable rights of the individual, and a great deal that was mere vague sentiment and pleasing speculation has been put forward as a fundamental principle," Wilson wrote. Instead he believed that government should be practical, and respond to the will of the people in the context in which history has placed it.
Wilson believed that in America the public was reaching a unity of spirit and intent, and that it was the job of the government to express their will. This unity of spirit made the safeguards written into the Constitution intended to prevent any one faction from domineering over a minority in America actually a hindrance to the progress of government. Wilson had to find some way around them to allow history to advance as it should. The result? In "The State," Wilson wrote that "Government does now whatever experience permits or the times demand."
If I may end by leaving my semi-neutral tone behind, Wilson's presidency showcased several examples of the dangers that can result when the federal government is not limited by the intended text of the Constitution. We all recall Wilson's fighting of World War I, but Wilson also sent troops all over Latin America without Congressional declarations of war, including an invasion of Mexico that outraged Congress and the public at large. On the free speech front Wilson set up something very close to a police state. During World War I his administration produced what was basically a propoganda department, and he signed the Espionage Act in 1917 and the Sedition Act in 1918. Criticize the government and you could end up in prison - and Wilson wanted the bills to remain in effect after the war.
Sources
"Woodrow Wilson and the Roots of Modern Liberalism" by Ronald Pestritto was most helpful for explicating Wilson's view of history and how it related to his political policies. "Liberal Fascism" by Jonah Goldberg was also helpful in this regard, and also contained details of Wilson's "police state." This was also discussed in "Lies My Teacher Told Me," by James Loewen, who also discussed Wilson's Latin America interventions. For Wilson's efforts to get us into World War I and his conduct of the war, see "The Politically Incorrect Guide to American History," by Thomas Woods.