How did progressive reformers amend the U.S. Constitution?

The Progressive Era resulted in four important amendments to the U.S. Constitution. The 16th Amendment (1913) gave the federal government the power to collect income taxes. Tax rates were progressive (in another sense of the word), or graduated. This means that those with higher incomes pay higher tax rates. The 17th Amendment (1913) led to the direct election of U.S. senators. (Under the original Constitution, written in 1787, state legislatures chose senators.) The 18th Amendment (1918) made the manufacture and sale of alcohol illegal, ushering in more than a decade of Prohibition, until this amendment was repealed in 1933. Finally, the 19th Amendment (1920) gave American women the right to vote. The crusade for women's suffrage, which lasted for decades, was the largest and most controversial reform movement of the Progressive Era. Progressives believed that these reforms would improve American political life, making the nation more democratic.