The map, if adopted, could also pose a problem for freshman Rep. Paul Gosar (R-Ariz.), whose district becomes more competitive. Former Rep. Ann Kirkpatrick (D-Ariz.), who Gosar unseated in 2010, is running to take back the seat and has already demonstrated the ability to raise large amounts of money to take him on.
If Giffords runs again, she is widely expected to win reelection without serious challenge. If the seat opens up, it will be competitive.
"We are encouraged by the fact that the commission is leaning toward a competitive map. We think that is good in terms of electing more moderates," said Arizona Democratic Party spokesman Andy Barr. "But we're not necessarily looking at this as any sort of guaranteed win."
Wasserman said Democrats were seeking to minimize the perception of their gains, lest the redistricting commission change the map before it is finalized after the public comment period.
"Democrats have every reason to downplay this map," he said. "I think it's going to generate a game of musical chairs."
Republicans blasted the map and accused the commission of abandoning its mandate to deliver an unbiased, balanced map.
"This gerrymandered map was drawn with an undeniable partisan purpose," Quayle said in a statement.
Arizona Gov. Jan Brewer (R) said she had been holding her tongue until now to give the commission room to work but vowed to formally weigh in on the map during the public comment period.
"I'll be silent no longer," she said. "Arizona voters are owed a redistricting process that is lawful and transparent."
— This post was updated at 11:51 a.m.