Final answer:
The U.S. faced internal conflict risks and prioritized domestic issues over foreign wars as arguments against entering WWI; supporting Allies and neutral rights were reasons for involvement. U.S. entry provided significant military and economic support to the Allies, leading to their victory.
Step-by-step explanation:
Arguments Against and For U.S. Entry into World War I
Two arguments against the United States entering World War I were the risk of igniting internal conflict due to the country's diverse population, including substantial Irish and German immigrant communities with potential sympathies contrary to the Allies, and President Woodrow Wilson's prioritization of domestic reform over foreign entanglements. The small size of the U.S. volunteer army also suggested limited initial impact on the war.
Arguments for entering the war included the need to support the Allies and uphold the rights of neutral nations, especially in response to unrestricted submarine warfare threatening American vessels and commerce. Furthermore, U.S. economic interests were increasingly tied to an Allied victory, given the loans and trade that favored the Allies.
The impact of U.S. participation on the outcome of World War I was significant. America's military contribution helped to break the stalemate on the Western Front, and its economic strength proved crucial in funding the Allies. The infusion of American troops and resources, bolstered by the country's position as a rising economic power, contributed to the eventual victory of the Allies.