Gemara

(Mishnah): A woman may not be secluded with Nochrim, for they are suspected of illicit relations;

23a - Contradiction (Mishnah): If a woman was taken captive by Nochrim, if this was due to money owed to her captor, she is permitted to her husband. If she was sentenced to die, she is forbidden to her husband.

Resolution (Ravina): L'Chatchilah she may not be secluded with Nochrim, but b'Di'eved we are not concerned.

Rejection: Perhaps (normally) we are concerned even b'Di'eved. Here is different, for her captor fears that if he has relations with her, her husband will not pay her debt to redeem her.

Support (Seifa): If she was taken for Nefashos, she is forbidden to her husband (because her captors have nothing to lose).

This cannot be challenged.

Kesuvos 26b (Rav Shmuel bar Rav Yitzchak): The Mishnah discusses only when Yisrael are in control. If the Nochrim are in control, even when taken for money she is forbidden to her husband.

Version #1 - Question (Rava - Mishnah): R. Yosi ha'Kohen and R. Zecharyah ben ha'Katzav testified about a girl who was taken for collateral for a loan in Ashkelon. Her family distanced themselves from her, even though the witnesses about her abduction said that she was never secluded.

Chachamim: If you believe the witnesses about the abduction, you should also believe them that she was not secluded!

Suggestion: Nochrim are in control in Ashkelon, and she needed witnesses (that there was no seclusion) only because she was taken for collateral. One taken for ransom would be permitted without witnesses!

Answer: No, the same applies even to one taken for ransom. The case happened to be that she was taken for collateral.

Version #2 - Support (Rava): The girl abducted in Ashkelon was permitted only due to the witnesses. Without witnesses, she would be forbidden!

Suggestion: We do not distinguish between being taken for collateral and being taken for ransom.

Rejection: No, being taken for collateral is more stringent.

Rishonim

Rambam (Hilchos Isurei Bi'ah 18:30): If a woman was taken for money she is permitted. If she was taken due to Nefashos she is forbidden to Kehunah. This is when Yisrael are in control and Nochrim fear them. When the Nochrim are in control, even if she was taken due to money, since she is in the Reshus of the Nochrim, she is forbidden, unless someone testified for her, like a captive.

Rosh (2:2): R. Elchanan says that Ravina teaches that b'Di'eved we are not concerned for bestiality, even if the animal was with the Nochri many days. We bring a proof from an Eshes Kohen who was abducted and in the Nochri's house many days. The Gemara rejects this. An abducted woman is permitted because her captor fears to lose his money, but if he had no monetary claim against her or her husband, she is forbidden even b'Di'eved.

Rosh (Kesuvos 2:29): The Mishnah permits a woman taken for money even if she is an Eshes Kohen. They will not rape her, lest they lose their money. The Gemara proves this, for it says that this is only when Yisrael are in control, but not when the Nochrim are in control. Surely this refers to an Eshes Kohen, for we bring a support from the girl abducted in Ashkelon. Her family distanced her. We must discuss Kohanim, for Bi'ah forbids a Bas Yisrael only to her husband, but not to the entire family! This implies that when Yisrael are in control, an Eshes Kohen is permitted. Also, in Avodah Zarah we say that a woman may not be secluded with Nochrim, for they are immoral. We asked from the Mishnah that permits if she was taken due to money. Granted, if the Mishnah permits an Eshes Kohen, this shows that we are not concerned lest they rape her. However, if it permits only an Eshes Yisrael, for we do not suspect lest she consented, but we forbid an Eshes Kohen lest she was raped, we should forbid seclusion with Nochrim! Rather, we are not concerned even for rape. Really, it should have taught that she is permitted to Kehunah, without distinguishing a Penuah (single girl) from an Eshes Ish. It discusses an Eshes Ish because the Seifa must teach about an Eshes Ish.

Ran (Kesuvos 11a DH Ela): Some derive from Rashi that our Mishnah discusses only an Eshes Yisrael. This is wrong. We conclude that when the Nochrim are in control, even if she was taken for money she is forbidden, for they are not concerned for losing their money. She is no worse than a captive, who is permitted to her Yisrael husband! We learn from the Kesuvah, which says 'if you are captured I will redeem you and return you for a wife' (50b). We asked (3b) that even if the mayor takes a Yisrael's Arusah before the Chupah, she is permitted to her husband! Esther was permitted to Mordechai (Megilah 13b). We permit an Eshes Ish seized by a thief. The Mishnayos before and after our Mishnah discuss Kehunah. This is why our Mishnah says 'a woman' (without specifying an Eshes Ish). The Seifa mentions her husband, to teach that even being taken due to her husband is considered for Nefashos. Also, it teaches that Nochrim do not fear even when she has a husband.

Ritva (Kesuvos 26b DH u'Mihu): Even though Esther was a Tzadekes, if we were concerned lest a regular woman consented, Mordechai should have been stringent, for she was made queen in place of Vashti.

Poskim

Shulchan Aruch (EH 7:11): If a woman was taken captive by Nochrim due to money, she is permitted even to Kehunah.

Rema: This is only if they (Yisre'elim) owe the Nochrim, for then the Nochrim fear to touch her, lest they lose principal. If they seized her in order to receive ransom for her, and they will not lose principal, she is forbidden to her husband if he is a Kohen.

Beis Yosef (DH Ishah): Rashi says that if she was seized for money, they fear losing their money, so they do not make her Hefker.

Chelkas Mechokek (16): One opinion in the Rosh and Tosfos permits even when she was taken for ransom. One should bring also the lenient opinions regarding Isurim mid'Rabanan.

Beis Shmuel (21): The lenient opinion in the Rosh permits whenever she was not taken due to Nefashos, even for ransom, when they do not fear losing money, and even when the Nochrim are in control. Ravina always permits b'Di'eved, just like one may buy animals from them. Witnesses were needed in Ashkelon because she was taken for collateral; we must say that that is different. Rashi says that since time for payment came, in their laws the collateral belongs to them. Since the Rosh and Poskim bring Rav, who says that it depends on who is in control, this shows that the Halachah does not follow Ravina. Maharik (160) brings all the Poskim who distinguish between seclusion and abduction, and not one permits b'Di'eved like Ravina. We permit only when they are concerned for loss of money. When we permit her for Kehunah, this is even if she is Penuyah. Also the Bach says so.

Gra (25): All the Poskim favor the latter answer (that we permit her only when her captor fears losing his money). The Gemara concluded that this cannot be challenged.

Shulchan Aruch (ibid): This is when Yisrael are in control and Nochrim fear them. When the Nochrim are in control, even if she was taken due to money, since she is in the Reshus of the Nochrim, she is forbidden, unless someone testified for her, like a captive.

Beis Yosef (DH v'Chasuv b'Hagahos): The Mordechai (Kesuvos 286) says that even when Yisrael are in control, we are stringent if there are Nochri courts in the city. The other Poskim did not say so; it seems that they disagree.