what is the meaning of "in the red corner" & "in the blue corner" . In the red corner, Mr. Trump has refused to tone down his abrasive rhetoric against women, Latinos, Muslims, African-Americans and the differently abled ...
This is a metaphor that combines a political reference and a sports reference.
In the sport of boxing, the opponents each have a corner where they go for rest between rounds of the fight. Referring to someone "in the ____ corner" is a reference to this "sport."
"Red" and "blue" in this context have to do with how in some past presidential election, TV news settled on coloring states that were voting for the Republican candidate in red, and the Democratic candidate in blue.
So what this whole phrase means is that Donald Trump is said to be expressing the Republican view.