ARIEL STONE
1. That the ancestors of the Karaite Jew are Egyptian.
2. That the Karaite party to the marriage swear a solemn and binding oath that s/he will behave according to Rabbanite law, without any deviation: that s/he will immerse in a pure mikvah according to the laws of conversion.
3. That none of the Karaite ’s ancestors were ever divorced.
In his responsum Rabbi Maselton apparently agrees with Rabbi Hazan’s approach. He is careful to state that this heter applies only to the Karaites of Egypt ,
who are completely distinguishable from the Rabbanites; there is no suspicion that the witnesses to their marriages are Rabbanite, and that therefore their kiddushin is kiddushin or at least safek-kiddushin. This is in contradistinction to those Karaite communities in which there is social mixing between Karaite and Rabbanite.*
MODERN TIMES
Contemporary Ashkenazi halakhic literature is very clear that Karaite and Rabbanite Jew do not intermarry. Korman explained that“since the days of the Rambam , the character of the Karaites has changed, and apropos of this, so has the attitude of halakha toward them.” Thus, the modern Ashkenazi attitude is seen as proceeding from the attitude of Isserles —that they are all safek mamzerim and are not to be admitted into the kahal—and of the Shulhan Arukh—that they are not to be considered anusim, or coerced, in their behavior or in their marriages“; and one who buys land from them is judged as one who buys from a Gentile.”
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