The Knesset has passed a new law which closes Israel’s doors to husbands who make their wives an agunah, refusing to give her a bill of divorce. The Conference of European Rabbis was behind the initiative, which has now been passed into law, barring recalcitrant husbands from seeking refuge in Israel.There is a peculiarity in Jewish law that a divorce has to be executed by the man, by giving a get, and if there is a civil divorce, the man is free to remarry and his children would not be a mamzer, which creates major complications for the child, while the wife's children would be.*
If a beis din in The Diaspora has labels a man a recalcitrant husband, not only will be barred from entering the country, but he will be detained by authorities at the airport as a deterrence towards compelling him to release his wife from an unwanted marriage.
As such, in many divorces, the man, either as a tactic, or just because they are an asshole, will refuse to give a get.
This problem is considered serious enough that Maimonides issued a ruling that it was acceptable to beat the husband to convince him to give the wife a get, so the move by the Israeli parliament is the least that they could have done.
It's actually more complicated