The purpose of government is to safeguard rights, among these are life, liberty, and the pursuit of happiness. The concept of "expanding rights" is not quite correct; these rights exist by virtue of birth, and or citizenship, were ignored or suppressed, and finally safeguarded by various acts. Legislatively, Amendments 13, 14 and 15, all ratified within 5 years of each other, abolished slavery, defined citizenship, and enforced suffrage, the franchise being further secured by Amendment 19 in 1920. Executively, President Truman in 1946 used executive powers to end segregation in government and military. The Civil Rights Acts of 1865, 1875, 1957, 1960, 1964, 1965, and 1968 furthered these causes. Judicially, Brown v. Board of Education struck down the "separate but equal" provision from Plessy v. Ferguson (1896) and allowed integration to begin to occur; this accelerated in 1969 when the court ordered desegregation be carried on "with all deliberate speed." In 1848, a Declaration of Sentiments was adopted at Seneca Falls, NY which stated that "All men and women are created equal." The Equal Rights Amendment, securing equality under the law regardless of sex, first proposed in 1923, finally failed ratification in 1981 being short by 3 states.
Source Note: Rise of the American Nation, Todd / Curti, 1972.
The Bill of Rights was passed the safeguard individual liberties. However, the rights guaranteed to all Americans haven't always been applied equally and fairly. The Bill of Rights was intended originally to restrain only the national government. Gradually, the Bill of Rights came to cover all Americans equally and to limit government power at all levels. Additional amendments to the Constitution and court rulings both played a part in this process.
Three amendments were passed after the Civil War to extend civil liberties to African Americans. These amendments were the 13th, 14th, and 15th Amendments-known as the "Civil War Amendments". The 13th Amendment (1865) officially outlawed slavery in the U.S. and outlawed any sort of forced labor, except as punishment for a crime. The 14th Amendment (1868) granted citizenship to all persons born or naturalized in the U.S; banned states from denying a person life, liberty, or property without due process of law; and banned states from denying any person equal protection under the laws. The 15th Amendment (1870) guaranteed voting rights to African Americans by outlawing denial of the right to vote on the basis of race, color, or previous condition of servitude.
In 1948, President Harry Truman ordered an end to segregation in the nation's armed forces. The civil rights laws of the 1960s certainly opened more doors for minorities. The Supreme Court's decision in Brown v. Board of Education of Topeka, Kansas (1954) ruled that racial segregation in the public schools was unconstitutional. Segregation violated the 14th Amendment's principle of equal protection under the law. The Civil Rights Act of 1963 was passed by Congress to set up commission on civil rights and created a division of civil rights in Justice Department. The Equal Pay Act of 1963 banned wage discrimination based on race, gender, religion, or national origin. The 24th Amendment (1964) outlawed poll taxes. Two years later the Supreme Court ruled that poll taxes were illegal in states elections as well. The Civil Rights Act of 1964 strengthened the 14th Amendments protections by banning discrimination in employment, voting, and public accommodations. The Voting Rights Act of 1965 empowered the federal government to intervene in voter registration discrimination. The Open housing Act of 1968 prevented people selling or renting homes from using certain forms of discrimination. The Equal Employment Opportunity Act of 1972 provided that businesses receiving federal funds must have affirmative action programs to increase the number of female and minority employees.
Although the Constitution didn't guarantee women the right to vote, it didn't explicitly deny them suffrage. The territory of Wyoming permitted women to vote in 1869, and several other territories and states did so as well in the years that followed. It was only in 1920, however, that the 19th Amendment protected the rights of women to vote in all national and state elections.