In the early 20th century, German researchers found additional evidence linking smoking to health harms, which strengthened the anti-tobacco movement in the Weimar Republic and led to a state-supported anti-smoking campaign. Early anti-tobacco movements grew in many nations from the middle of the 20th century. The 1933–1945 anti-tobacco campaigns in Nazi Germany have been widely publicized, although stronger laws than those passed in Germany were passed in some American states, the UK, and elsewhere between 1890 and 1930. After 1941, anti-tobacco campaigns were restricted by the Nazi government. The German movement was the most powerful anti-smoking movement in the world during the 1930s and early 1940s. However, tobacco control policy was incoherent and ineffective, with uncoordinated and often regional efforts by many actors. Obvious measures were not taken, and existing measures were not enforced. Some Nazi leaders condemned smoking and several of them openly criticized tobacco consumption, but others publicly smoked and denied that it was harmful. There was much research on smoking and its effects on health during Nazi rule, and it was the most important of its type at that time. A directly supported tobacco research institute produced work of only marginal scientific importance, but substantial academic work was done privately, with little to negative official support. Adolf Hitler's personal distaste for tobacco and the Nazi reproductive policies were among the motivating factors behind the Nazi campaigns against smoking. The Nazi anti-tobacco campaign included banning smoking in trams, buses, and city trains, promoting health education, limiting cigarette rations in the Wehrmacht, organizing medical lectures for soldiers, and raising the tobacco tax. The Nazis also imposed restrictions on tobacco advertising and smoking in public spaces, and regulated restaurants and coffeehouses. However, these measures were widely circumvented or ignored. The movement did not reduce the number of smokers.