The relationship between Israel’s immigration policy and Jewish law seems to pop up on this forum with annoying regularity, so I’m starting a thread which will hopefully address the issue once and for all, and which I can point to the next time the issue comes up.
First, check out the text of the Law of Return: http://www.knesset.gov.il/laws/special/eng/return.htm
Now, look at the history in the ever-reliable wikipedia.
One explanation for this amendment is that the Law of Return attempts to provide sanctuary as a citizen in Israel to anyone who would be persecuted under the Nuremberg Laws. As the Nuremberg Laws did not use a halakhic definition in its definition of Who is a Jew, the Law of Return definition for citizenship eligibility is not halakhic, either. The Law of Return merely provides citizenship for anyone covered under the Nuremberg Laws, but does not necessarily denote Jewish status to those granted citizenship.
A second explanation is that in order to increase immigration levels so as to offset the “demographic threat” posed by the continuing presence and growth of the Palestinian population, the law expanded the base group of those eligible to immigrate to Israel.  A third explanation promoted by religious Jews is that the overwhelmingly secular leadership in Israel sought to undermine the influence of religious elements in Israeli politics and society by allowing more secular Jews and their non-Jewish spouses to immigrate.
For a nice discussion of the definition of Judaism for immigration to Israel vis a vis the halakhic definition, I’m going to steal someone else’s discussion of Neusner’s “Hitler is not my Posek.”
>A year or two ago I read a piece by Jacob Neusner entitled, “Hitler is not
>my Posek,” in which he criticized this reasoning. In essence, it makes
>Hitler a supreme halakhic authority, greater than chazal.
(FYI, halacha refers to the Laws of the Torah, and the rabbinacal case
law that has been built around it refering to what is permitted,
forbidden, and required by Jews.)
This is based on two assumptions, both of which are highly
questionable. (I haven’t seen Neusner’s peice, but I argue with your
summary of it.)
- It is assumed that the State of Israel is either a halachic state,
or should base its laws apon halacha.
Israel is not based on halacha, and the few laws it does have based on
halacha, weaken both its moral legitamacy and its societal cohesion.
Claimng that Hitler is made into a halachic authority because of the
actions of Israel would require Israel to be controled by halacha,
which it is not.
- That the national homeland of the Jews should allow people viewed
as Jews by their enemies to be killed.
Israel exists to be a homeland, where Jews can go to when they are not
welcome in other countries. To refuse entry to someone being
persecuted because they are seen as a Jew would be a fundamental
mistake. Allowing them to enter the country as Jews means not that
Hitler is made by us into a halachic authority, but that we
acknowledge his physical ability to kill innocents, and act with
rachmones towords them.
Allowing people whose halachic status as Jews might be questioned to enter
Israel is a moral requirement for Israel. This is both to assert its
morality, and also to demonstrate that it is not dominated by nudniks
who would let someone be persecuted for being Jewish when he was
unable to demonstrate it is true.
For a discussion of racial anti-semitism, we can again turn to wikipedia:
Modern European antisemitism has its origin in 19th century theories—now mostly considered as pseudo-scientific—that said that the Semitic peoples, including the Jews, are entirely different from the Aryan, or Indo-European, populations, and that they can never be amalgamated with them. In this view, Jews are not opposed on account of their religion, but on account of their supposed hereditary or genetic racial characteristics: greed, a special aptitude for money-making, aversion to hard work, clannishness and obtrusiveness, lack of social tact, low cunning, and especially lack of patriotism.
While enlightened European intellectual society of that period viewed prejudice against people on account of their religion to be declassé and a sign of ignorance, because of this supposed ‘scientific’ connection to genetics they felt fully justified in prejudice based on nationality or ‘race’. In order to differentiate between the two practices, the term antisemitism was developed to refer to this ‘acceptable’ bias against Jews as a nationality, as distinct from the ‘undesirable’ prejudice against Judaism as a religion. Concurrently with this usage, some authors in Germany began to use the term ‘Palestinians’ when referring to Jews as a people, rather than as a religious group.
Now, can we please stop talking about the Law of Return as a religious law? Pretty please?
EDIT: removed specific references to one person.