Question

Why did World War I seem like an ineffective effort to many Americans? How did this affect Americans' views of war?

Answer 1

Many Americans were against getting involved in a War that was being fought in Europe though begrudgingly Americans became aware there was danger on the High Seas as Atlantic waters became host to submarines while warships dueled in the waters of the South Pacific and Atlantic. 
Many Americans, particularly the Wobbles, the IWW International Workers of World (rightly) argued that the main reason for fighting would be to profit by various means profits that would mostly land in the pockets of International Bankers and Industrialist, the Halliburton of the times. 

Answer 2

Answer:

Because they saw the conflict as a European war, with interests and ideas that did not match with the Americans. The efforts to send men to fight in a war that, according to many Americans, it was useless, it was a waste of time and money. Even with the bombarding and sinking of the Lusitania in 1917, and the constant patrolling of German submarines in the Atlantic Ocean, the majority of American citizens didn't see a need for this war. They bought the war, as we know. However, after the conflict, the point of view about the conflict, and the reasons to start one changed enormously, and the isolationist politics returned with strength.

Explanation: