What is the test for upholding a finding of fact by an Immigration Judge in a deportation proceeding?

Factual findings by the Immigration Judge in a deportation proceeding must be upheld if supported by substantial evidence. Zepeda-Melendez v. INS, 741 F.2d 285, 289 (9th Cir.1984). Here the Immigration Judge found petitioner's allegations of threats of persecution lacking credibility. The majority has chosen to substitute its own findings of fact for those of the Immigration Judge. According the deference owed the findings of the Immigration Judge, I conclude that he did not err in concluding that petitioner's allegations did not demonstrate either a clear probability of persecution or a well-founded fear of persecution.