Answer:
The favor that the author talks about in the title is favor to New Orleans by American citizens.
Step-by-step explanation:
"An Editorial: It's time for a nation to return the favor" is an article published on November 20, 2005.
The favor that the author is talking about in the title is the favor New Orleans have on America. The author lists the resources that New Orleans offers to America, to which author is obliged. But the author also asks the citizen to sign Congress's petition for New Orleans.