How did the Wilson administration and its supporters respond to antiwar efforts, and how effective were these responses?

For three years after numerous Eastern Hemisphere countries declared war on each other and supported alliances in the Great War, the United States maintained an official position of neutrality. The anti-war movement was large and multifaceted, including women with a large suffragist component, labor activists, Socialists, and other progressives from urban and rural areas. For many, it was Europe's war, and the United States might play a vital role in mediation and arbitration.
Because the administration's policy was neutrality, Wilson often met with various anti-war movement leaders. As public sentiment changed, the National Women Suffrage Association brokered a deal to switch their position in exchange for Wilson's support of women's votes.
Between pressure from the hawks and events such as the Lusitania's sinking, the climate changed. Once the United States committed to entering the war in 1917, those opposing it were targeted and often ruthlessly pursued. Many were jailed for breaking newly passed laws against sedition.
https://constitutioncenter.org/blog/war-against-war-americans-for-peace-in-world-war-i