What is the test for admitting an impeached spouse's criminal record?

La Forest J. in Corbett, at 740-41, adopted the following principle from Gordon v. United States, 383 F.2d 936 (1967), at 940: As a general guide, those convictions which are for the same crime should be admitted sparingly, one solution might well be that discretion be exercised to limit the impeachment by way of a similar crime to a single conviction and then only when the circumstances indicate strong reasons for disclosure, and where the conviction directly relates to veracity.