WASHINGTON -- Two weeks before the Iowa caucus, the race for president, while tightening among Democrats, is wide open on the Republican side, highlighting the unusual fluidity of the first campaign for the White House in over a half-century that doesn't include an incumbent president or vice president.

A new Wall Street Journal/NBC News poll shows that Rudy Giuliani has lost his national lead in the Republican field after a flurry of negative publicity about his personal and business activities, setting the stage for what...