With the last House race decided over the weekend,

English as a Second Language English Vocabulary, Grammar and Idioms
1

With the last House race decided over the weekend, the conflict between a Democratic president convincingly re-elected to a second term and the House Republicans [color=red]who held their majority illustrates a striking dichotomy in the nation’s body politic: the president and a majority of senators, including a growing number of Republicans, back compromise on tax rates and say the public is on their side, and a majority of the House, in artfully drawn districts, claim just the opposite.

  1. I think the subject of “illustrates” is “the conflict”, is it?
  2. I don’t understand what does the red part suggest?
  3. I can’t work out the underlined part. Is “back” verb here?
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  1. Correct.
  2. They kept their majority: They had a majority before, and they still have one now.
  3. Yes. “back compromise” = “support compromise”.