Women activists continued to press Wilson for suffrage after his second term began. A new organization, the National Woman’s Party, worked to pass an amendment to the US Constitution. In January 1917, suffragists began demonstrating outside the White House. Shortly after Wilson’s inauguration in March, three American ships were sunk by German submarines, and Wilson reluctantly decided to enter the war, asking Congress to do so in early April. That same day, a constitutional amendment for woman suffrage was introduced. On April 6, Congress declared war, and this eventually overshadowed the suffrage issue.

That same year, The Psychology Committee of the National Research Council was formed and led by Robert Yerkes, the president of the American Psychological Association. Marston’s experiments to detect lies from truth could potentially be applied to spies in a war, and he soon contacted Yerkes to inquire about continuing his work. Herbert Langfeld, Marston’s undergraduate adviser, agreed to allow him to work in the lab on campus. Yerkes set up the Committee on Tests for Deception, and Marston provided research. Initial experiments on students were promising, so Yerkes had Marston apply his methods to actual criminal defendants. He took on 20 cases, and his conclusion in every one, based on blood pressure measurements, was eventually verified by evidence.