Hillary will discourage him.
Is she going to leak that his birth name is Faruk Abdullah and he spent the first 40 years of his life in a mosque?
Probably in her interest for him to run. When you're the frontrunner, you want as many rivals as possible. A two man (err, person) race is where frontrunners get upset. When its a frontrunner versus everyone else, its hard for one challenger to climb over the rest to take on the front runner.
I'd say that especially goes for this year. Obama is getting a ton of press for being the "first" black candidate (Jesse Jackson, Al Sharpton and Alan Keyes excepted I guess), Richardson will get the same treatment for being the first Hispanic candidate. That will mean less press for Obama and the rest of the Dems.
"Hillary will discourage him."
No she won't. Richardson is the VP on someones ticket. The RATS will need the Hispanic vote as well as New Mexico since NM usually votes Republican.