Complex sentence: The mayor Sergio Massa organized the coalition United for a New Alternative to run for the 2015 presidential election and invited Rodríguez Saá to join, but he refused to join and ran with his own party, Federal Commitment.
Split into simpler sentences: The mayor Sergio Massa organized the coalition United for a New Alternative to run for the 2015 presidential election and invited Rodríguez Saá to it. He refused to join it and ran with his own party, Federal Commitment.