From the WhiteHouse Bulletin -Hillary Clinton's big victory in the Pennsylvania primary this week has deeply impressed John McCain and his inner circle. The Republican presidential candidate believes that the win shows how formidable a candidate Clinton is and how strong she would be if she wins the Democratic nomination. One lesson learned by the McCain team: "Never count the Clintons out" because they keep coming back from adversity. McCain insiders say Senator Clinton ran a poor campaign until recently, failing to see the threat from Barack Obama and taking too long to counteract it. The upshot: "The Clintons aren't invincible," says a McCain strategist, "but we can see how ruthless they can be." The McCain forces think Obama can still win the Democratic nomination if he explains his policies in more detail, gives the media more access to convey his engaging personality and likeability, gets less thin-skinned about criticism, and shows more of a sense of humor.