Criticism, even the most scathing criticism, of the Israeli government or its actions is not by itself antisemitic.
But according to Hannah Rosenthal, the US State Department’s Special Envoy to Monitor and Combat Anti-Semitism:
Our State Department uses Natan Sharansky’s framework for identifying when someone or a government crosses the line – when Israel is demonized, when Israel is held to different standards than the rest of the countries, and when Israel is delegitimized. These cases are not disagreements with a policy of Israel, this is anti-Semitism.
I agree, and further:
When someone maintains friendly relations with notorious antisemites; demonizes Israel and holds it to a different standard from other countries, especially on matters of human rights and self-defense; focuses laser-like on Israel’s crimes and misdeeds (some of which are imaginary or exaggerated, others of which are all too real) while ignoring, excusing, glorifying or doing propaganda for governments of other countries which are far less free and do far worse (see also here, here and here); trivializes the Holocaust by comparing Israel’s actions in Gaza to the systematic starvation to death and ultimate slaughter of more than 300,000 Jews in the Warsaw Ghetto; says that of all the countries in the world, the only one that has no right to exist is the one with a Jewish majority; and when almost half of the world’s Jews live in that state and the great majority of Jews living elsewhere support it– then the burden is not on me to prove that person is antisemitic. Rather the burden is on him to prove that he is not.