Norman Podhoretz cites Nathan Glazer for the view that "Israel is the religion of American Jews." This is precisely the problem. When religious loyalty is put above patriotism--as it should be--believers can be charged with political disloyalty, as Catholics were before the 1960s in America. However, for non-Jews religious loyalty has not usually meant loyalty to a particular secular state or religious territory. For Catholics since the loss of the Papal States in 1870, religion has not involved maintenance of a particular political order.
As the object of Jews' religious devotion, Israel does unfortunately raise unique questions of loyalty. Had the early Zionist view prevailed that Jews not returning to a Jewish state would disappear through conversion or assimilation, the problem would not exist. That is obviously not the current reality.