Analysis by Ronald Brownstein By the standards Democratic Sens. Joe Manchin and Kyrsten Sinema have set for federal action on voting rights, the 14th and 15th amendments to the Constitution — two pillars of the post-Civil War effort to ensure equality for all Americans — would never have become law. Every Democrat in Congress at the time voted against both the 14th Amendment, which sought to guarantee all Americans (including the freed slaves) equal treatment under the law, and the 15th Amendment (which attempted to ensure the freed slaves the right to vote). Yet, despite that opposition, the Abraham Lincoln-era Republican Party considered the amendments so critical to expunging the legacy of slavery and creating a new national floor of civil rights for all Americans that they muscled them through Congress with barely any dissenting votes from their members in each chamber.