Democratic vice presidential hopeful Sen. Joseph Biden (Del.) on Sunday warned Sen. Joe Lieberman (ID-Conn.) that he will have to make a “tougher judgment” on which party to affiliate himself with following the November elections, in the wake of Lieberman’s appearance at the GOP convention where he gave a speech harshly critical of Democratic presidential nominee Sen. Barack Obama (Ill.). Biden, appearing Sunday on “Meet the Press,” said he is disappointed with Lieberman’s decision to back GOP presidential hopeful Sen. John McCain (Ariz.) and that his decision would make his life in the Senate more difficult following the election. “Every time I see Joe these days, I walk up and I say, ‘Say it ain’t so, Joe — say it ain’t so.’ … Look, Joe has made a judgment. Joe is going to have to make a tougher judgment when this election is over,” Biden said. Biden joins Senate Majority Leader Harry Reid (D-Nev.) and Speaker Nancy Pelosi (D-Calif.) in the latest round of criticism directed at Lieberman.