"The world must be made safe for democracy. Its peace must be planted upon the tested foundations of political liberty. We have no selfish ends to serve. We desire no conquest, no dominion. We seek no indemnities for ourselves, no material compensation for the sacrifices we shall freely make. … It is a fearful thing to lead this great peaceful people into war, into the most terrible and disastrous of all wars, civilization itself seeming to be in the balance. But the right is more precious than peace, and we shall fight for the things which we have always carried nearest our hearts,—for democracy, for the right of those who submit to authority to have a voice in their own Governments, for the rights and liberties of small nations, for a universal dominion of right by such a concert of free peoples as shall bring peace and safety to all nations and make the world itself at last free."—President Woodrow Wilson, 1917

In the aftermath of World War I, what was the most serious obstacle to implementing the goals stated in Wilson's war message?

Congress's reluctance to be drawn into European matters
European countries' unwillingness to abide by these principles
The American people's fear of an economic downturn
A lack of safeguards to prevent future colonialism and militarism