Complex sentence: In July 2000, Cheney was chosen by presumptive Republican presidential nominee George W. Bush as his running mate in the 2000 presidential election, where they defeated Democratic opponents, then Vice President Al Gore and Senator Joe Lieberman.
Split into simpler sentences: In July 2000, Cheney was chosen by presumptive Republican presidential nominee George W. Bush as his running mate in the 2000 presidential election. They defeated their Democratic opponents, incumbent Vice President Al Gore and Senator Joe Lieberman.