NEW YORK (Reuters) - A US federal judge has dismissed attempts by telephone service provider IDT Corp. to scuttle the sale of bankrupt Global Crossing Ltd's assets to two Asian investors. IDT, citing a threat to US national security, said it would mount a rival $255 million bid to acquire Global Crossing's high-speed network, seeking to edge out a rival bid by Hong Kong's Hutchison Whampoa Ltd and Singapore Technologies Telemedia Pte. But in a court hearing, Judge Robert Gerber, of the US bankruptcy court in Manhattan, refused to allow IDT's chief executive Jim Courter to present his case.