Complex sentence: The appointment brought on a storm of criticism from Henry Cabot Lodge, who had since been elected to the Senate, dominated the Republican Party in Massachusetts, and had expected to have a say in choosing a cabinet nominee in return for his support of McKinley.
Split into simpler sentences: The appointment brought on a storm of criticism from Henry Cabot Lodge. Lodge had been elected to the Senate, dominated the Republican Party in Massachusetts, and had expected to have a say in choosing a cabinet nominee in return for his support of McKinley.