Bush just delivered a major speech in Pennslyvania. The main question now is this: why wasn't he like that in the debates?
Debates involve someone challenging the points you're making. Speeches don't -- especially speeches where the audience has been screened to only allow those who already support the points being made.
If Bush wants to win the upcoming debtates, he needs to demonstrate that he can defend his position on the issues based on the merits of his policies rather than just expecting everyone to follow along because he says so. In other words, Bush needs to demonstrate his "strong leadership" skills that the Republicans are constantly touting.