Complex sentence: Eastwood had endorsed Mitt Romney for the 2012 United States presidential election earlier that month, and spent much of his speech's running time on a largely improvised routine in which he addressed an empty chair that represented President Barack Obama.
Split into simpler sentences: Eastwood had endorsed Mitt Romney for the 2012 United States presidential election earlier that month. Eastwood spent much of his speech time on a largely improvised routine addressing an empty chair representing President Barack Obama.