By Zachary A. Goldfarb The 2004 Democratic presidential nominee accused the campaign of Sen. John McCain of trying to impugn the character of Sen. Barack Obama in this year's presidential race. "They're trying to scare you," Sen. John F. Kerry (Mass.) said on NBC's "Meet the Press." "They are engaged in character assassination." "They've decided they can't win on the issues, so they've decided to try to destroy his character," Kerry said, quoting his Senate colleague Russ Feingold (D-Wis.). Kerry's comments alluded to a McCain TV advertisement that debuted last week. The ad, which compared Obama to celebrities such as Paris Hilton and Britney Spears, raised an important point, McCain ally Sen. Joseph I. Lieberman (I-Conn.) said on NBC. "Notwithstanding his celebrity status, is Barack Obama ready to serve?" said Lieberman, the 2000 Democratic vice presidential candidate. He said the question was particularly relevant after Obama's trip to Europe, where ...