Complex sentence: Clay and other western spokesmen demanded that Spain also give up Texas, but that proposal was defeated by the Senate, which ratified the treaty a second time on 19 February 1821, following ratification by Spain on 24 October 1820.
Split into simpler sentences: Clay and other western spokesmen demanded that Spain also give up Texas. This proposal was defeated by the Senate, which ratified the treaty a second time on 19 February 1821 following ratification by Spain on 24 October 1820.