Arver v. United States, 245 U.S. 366 (1918), also known as the Selective Draft Law Cases, was a United States Supreme Court decision which upheld the Selective Service Act of 1917, and more generally, upheld conscription in the United States. The Supreme Court upheld that conscription did not violate the Thirteenth Amendment's prohibition of involuntary servitude, or the First Amendment's protection of freedom of conscience.

The Solicitor General's argument, and the court's opinion, were based primarily on Kneedler v. Lane, which was actually multiple opinions of the Supreme Court of Pennsylvania during the American Civil War that upheld the Enrollment Act, and Vattel's The Law of Nations (1758).^[1][2] The reliance on the Kneedler v. Lane decisions of the Pennsylvania Supreme Court have been questioned on multiple occasions.^[2][3]

As reasoning for its decision, laws of the following governments of sovereign states were given as listed in The Statesman's Yearbook for 1917 as enforcing military service:

• Argentina^[4]
• Austria-Hungary^[5]
• Belgium^[6]
• Brazil^[7]
• Bulgaria^[8]
• Bolivia^[9]
• Canada^[10]
• Colombia^[11]
• Chile^[12]
• China^[13]
• Denmark^[14]
• Ecuador^[15]
• El Salvador^[16]
• France^[17][18]
• Greece^[19]
• Germany^{[20][21][22][23]}
• Guatemala^[24]
• Honduras^[25]
• Italy^[26]
• Japan^[27]
• Mexico^[28]
• Montenegro^[29]
• Netherlands^[30]
• Nicaragua^[31]
• Norway^[32]
• Peru^[30]
• Portugal^[33]
• Romania^[34]
• Russia^[35]
• Serbia^[36]
• Siam^[37]
• Spain^[38]
• Switzerland^[39]
• Turkey^[40]