Complex sentence: Congressional elections in 1890 went against the Republicans, several party leaders withdrew their support for President Harrison, although he had cooperated with Congressional Republicans on legislation, and it was clear that Harrison would not be re-nominated unanimously.
Split into simpler sentences: Congressional elections in 1890 went against the Republicans, and several party leaders withdrew their support for President Harrison, although he had cooperated with Congressional Republicans on legislation. It was clear that Harrison would not be re-nominated unanimously.