<P> The American entry into World War I came in April 1917, after more than two and a half years of efforts by President Woodrow Wilson to keep the United States out of the war . Apart from an Anglophile element urging early support for the British, American public opinion reflected that of the president: the sentiment for neutrality was particularly strong among Irish Americans, German Americans and Scandinavian Americans, as well as among church leaders and among women in general . On the other hand, even before World War I had broken out, American opinion had been more negative toward Germany than towards any other country in Europe . Over time, especially after reports of atrocities in Belgium in 1914 and following the sinking of the passenger liner RMS Lusitania in 1915, the American people increasingly came to see Germany as the aggressor in Europe . </P> <P> As U.S. President, it was Wilson who made the key policy decisions over foreign affairs: while the country was at peace, the domestic economy ran on a laissez - faire basis, with American banks making huge loans to Britain and France--funds that were in large part used to buy munitions, raw materials and food from across the Atlantic . Until 1917, Wilson made minimal preparations for a land war and kept the United States Army on a small peacetime footing, despite increasing demands for enhanced preparedness . He did however expand the United States Navy . </P>

When did the usa enter world war 1