Truman announces development of H-bomb U.S. President Harry S. Truman publicly announces his decision to support the development of the hydrogen bomb, a weapon theorized to be hundreds of times more powerful than the atomic bombs dropped on Japan during World War II. Five months earlier, the United States had lost its nuclear supremacy when the Soviet Union successfully detonated an atomic bomb at their test site in Kazakhstan. Then, several weeks after that, British and U.S. intelligence came to the staggering conclusion that German-born Klaus Fuchs, a top-ranking scientist in the U.S. nuclear program, was a spy for the Soviet Union. These two events, and the fact that the Soviets now knew everything that the Americans did about how to build a hydrogen bomb, led Truman to approve massive funding for the superpower race to complete the world’s first “superbomb,” as he described it in his public announcement on January 31. On November 1, 1952, the United States successfully detonated “Mike,” the world’s first hydrogen bomb, on the Elugelab Atoll in the Pacific Marshall Islands. The 10.4-megaton thermonuclear device, built upon the Teller-Ulam principles of staged radiation implosion, instantly vaporized an entire island and left behind a crater more than a mile wide. The incredible explosive force of Mike was also apparent from the sheer magnitude of its mushroom cloud–within 90 seconds the mushroom cloud climbed to 57,000 feet and entered the stratosphere. One minute later, it reached 108,000 feet, eventually stabilizing at a ceiling of 120,000 feet. Half an hour after the test, the mushroom stretched 60 miles across, with the base of the head joining the stem at 45,000 feet. Three years later, on November 22, 1955, the Soviet Union detonated its first hydrogen bomb on the same principle of radiation implosion. Both superpowers were now in possession of the “hell bomb,” as it was known by many Americans, and the world lived under the threat of thermonuclear war for the first time in history. 1865 House passes the 13th Amendment On this day in 1865, the U.S. House of Representatives passes the 13th Amendment to the Constitution, abolishing slavery in America.The amendmentread, “Neither slavery nor involuntary servitude…shall exist within the United States, or any place subject to their jurisdiction.” When the Civil War began, President Abraham Lincoln’s professed goal was the restoration of the Union. But early in the war, the Union began keeping escaped slaves rather than returning them to their owners, so slavery essentially ended wherever the Union army was victorious. In September 1862, Lincoln issued the Emancipation Proclamation, freeing all slaves in areas that were still in rebellion against the Union. This measure opened the issue of what to do about slavery in border states that had not seceded or in areas that had been captured by the Union before the proclamation. In 1864, an amendment abolishing slavery passed the U.S. Senate but died in the House as Democrats rallied in the name of states’ rights. The election of 1864 brought Lincoln back to the White Housealong withsignificant Republican majorities in both houses, so it appeared the amendment was headed for passage when the new Congress convened in March 1865. Lincoln preferred that the amendment receive bipartisan support–some Democrats indicated support for the measure, but many still resisted. The amendment passed 119 to 56, seven votes above the necessary two-thirds majority. Several Democrats abstained, but the 13th Amendment was sent to the states for ratification, which came in December 1865. With the passage of the amendment, the institution that had indelibly shaped American history was eradicated. 1917 Germany resumes submarine warfare On January 31, 1917, Germany announces the renewal of unlimited submarine warfare in the Atlantic, and German torpedo-armed submarines prepare to attack any and all ships, including civilian passenger carriers, said to be sited in war-zone waters. Three days later, the United States broke diplomatic relations with Germany, and just hours after that the American liner Housatonic was sunk by a German U-boat. None of the 25 Americans on board were killed, and all were later picked up by a British steamer. When World War I erupted in 1914, President Woodrow Wilson pledged neutrality for the United States, a position that the vast majority of Americans favored. Britain, however, was one of America’s closest trading partners, and tension soon arose between the United States and Germany over the latter’s attempted quarantine of the British isles. Several U.S. ships traveling to Britain were damaged or sunk by German mines, and in February 1915 Germany announced unrestricted warfare against all ships, neutral or otherwise, that entered the war zone around Britain. One month later, Germany announced that a German cruiser had sunk the William P. Frye, a private American vessel that was transporting grain to England when it disappeared. President Wilson was outraged, but the German government apologized and called the attack an unfortunate mistake. The Germans’ most formidable naval weapon was the U-boat, a submarine far more sophisticated than those built by other nations at the time. The typical U-boat was 214 feet long, carried 35 men and 12 torpedoes, and could travel underwater for two hours at a time. In the first few years of World War I, the U-boats took a terrible toll on Allied shipping. In early May 1915, several New York newspapers published a warning by the German embassy in Washington that Americans traveling on British or Allied ships in war zones did so at their own risk. The announcement was placed on the same page as an advertisement of the imminent sailing of the British-owned Lusitania ocean liner from New York to Liverpool. On May 7, the Lusitania was torpedoed without warning just off the coast of Ireland. Of the 1,959 passengers, 1,198 were killed, including 128 Americans. The German government maintained that the Lusitania was carrying munitions, but the U.S. demanded reparations and an end to German attacks on unarmed passenger and merchant ships. In August, Germany pledged to see to the safety of passengers before sinking unarmed vessels but in November sunk an Italian liner without warning, killing 272 people, including 27 Americans. Public opinion in the United States began to turn irrevocably against Germany. In 1917, Germany, determined to win its war of attrition against the Allies, announced the resumption of unrestricted warfare. The United States broke off relations with Germany, and on February 22 Congress passed a $250 million arms appropriations bill intended to make the United States ready for war. Two days later, British authorities gave the U.S. ambassador to Britain a copy of the “Zimmermann Note,” a coded message from German foreign secretary Arthur Zimmermann to Count Johann von Bernstorff, the German ambassador to Mexico. In the telegram, intercepted and deciphered by British intelligence, Zimmermann stated that, in the event of war with the United States, Mexico should be asked to enter the conflict as a German ally. In return, Germany promised to restore to Mexico the lost territories of Texas, New Mexico, and Arizona. On March 1, the U.S. State Department published the note, and American public opinion was galvanized against Germany. In late March, Germany sunk four more U.S. merchant ships, and on April 2 President Wilson appeared before Congress and called for a declaration of war against Germany. On April 4, the Senate voted 82 to six to declare war against Germany. Two days later, the House of Representatives endorsed the declaration by a vote of 373 to 50, and America formally entered World War I. On June 26, the first 14,000 U.S. infantry troops landed in France to begin training for combat. After four years of bloody stalemate along the western front, the entrance of America’s well-supplied forces into the conflict was a major turning point in the war. When the war finally ended, on November 11, 1918, more than two million American soldiers had served on the battlefields of Western Europe, and some 50,000 of these men had lost their lives.