the dilemna for the Obama campaign

After being defeated in Ohio and Texas (Rhode Island was clearly going to vote for Clinton), the Obama campaign is grappling to find a way to respond to Clinton's attack tactics that seem to have paid off. The question is : do you have to go negative to win? Would that undermine Barack Obama's offer of a new way of doing politics?
Samantha Power, an Obama senior adviser on foreign policy issues, has just resigned after an off the record comment to a Scottish newspaper describing Sen. Clinton as "a monster". Moreover the Obama campaign has been recently caught twice being rather inconsistent :
- over NAFTA : Obama was launching a staunch criticism of the trade agreement to seduce voters in Ohio while one of his advisers was said to have been reassuring Canadian officials that this was nothing more than an electoral tactic (this is being referred to as the "Nafta-gate"
- over the plan to leave Iraq : the selfsame Mrs Power has said that Obama would probably not implement the plan to return the troops as he has advocated it.

A quick point on the Texas primary contest : you may have heard that Texas has both a primary and a caucus. The latter was won by B. Obama, which explains why Clinton's narrow victory should not be over-emphasized. Moreover the number of delegates per district is apportioned according to the way the state senate disctricts voted in the last elections : the disctricts which ovted most heavily Democratic in the last State Senate elections get more delegates than a district that voted strongly Republican. This system was considered unfair by the Clinton campaign since this gave a clear advantage to the African-American districts over the Latino districts which were perhaps more evenly split between the Democrats and the GOP and less electorally active.

Today the State of Wyoming is voting : how will this impact the momentum of Hillary Clinton : will it be reinforced or not?