Because Barack obama is being mean to her. Earlier today he released this memo about Hillary's remarks about us being more safe;
http://www.tpmcafe.com/blog/electioncentral/2007/jun/04/obama_camp_details_his_claim_that_world_is_more_dangerous_since_9_11Barack Obama's campaign has just sent out a memo to "interested parties" -- read: reporters, pundits, fixers, etc. -- detailing his claim yesterday that the world is more dangerous due to President Bush's policies.
The Obama memo is interesting because it appears designed to call attention (without directly saying so) to a difference at last night's debate between Obama and Hillary on the question of whether the world's a safer place.
The memo observes (without mentioning Hillary's name) that at the debate there was "disagreement over whether or not America is safer since the 9/11 attacks on our nation."
The disagreement between the two Democratic candidates was not spectacularly pronounced. Obama opined that "we live in a more dangerous world, not a less dangerous world, partly as a consequence of this president's actions." Meanwhile, Hillary, in response to a different question, said: "I believe we are safer than we were. We are not yet safe enough." Not a great deal of daylight there between the two, but perhaps noteworthy.
After that memo came out Schumer released this statement(found on this link)
http://www.tpmcafe.com/blog/electioncentral/2007/jun/04/schumer_leaps_to_hillarys_defense_against_obamaWhat I find funny is that Dick Durbin, who is Obama's biggest cheerleader and Schumer are roomies.