Complex sentence: In the United States the movement is associated with Christian religious groups, especially the Catholic Church, and is frequently, but not exclusively, allied with the Republican Party, and seeks to restrict abortion with legislation such as the Human Life Amendment.
Split into simpler sentences: In the United States the movement is associated with several Christian religious groups, especially the Catholic Church, and is frequently, but not exclusively, allied with the Republican Party. The movement seeks to restrict abortion with legislative changes, such as the Human Life Amendment.