Out of many tragic situations come new insights and new heroes. This may be the case now with Gabby Giffords' shooting.
Gabby Giffords has been known as a moderate Democrat - no liberal - who has the respect and friendship of members of both parties in the House. She has a very positive can-do attitude and tons of energy for problem solving. She is relatively young. Hence I wonder if this scenario has merit for the country and the Democratic Party:
Suppose Gabby makes a full recovery by the end of 2011:
then next January Joe Biden - age 69 - announces that he will not continue on the ticket as VP with Obama . Instead he will either retire or - if Hillary prefers - move to Secretary of State. Obama then announces that he has asked young, energetic, moderate, respected Rep. Giffords to be his running mate in 2012. This would energize the party, draw many independent voters, and be a national repudiation of violence in politics.
And as a bonus:
it would be the first move in the possible election of a woman as President in 2016.