The Israel lobby is the illustration par excellence of the single issue. If you really have a single issue, and nothing else matters to you, and you have a fair amount of money to throw around, you can have a very outsized impact on US politics. And of course you have to be absolutely rigid; no negotiating at all, no half a loaf; it’s either unconditional surrender and slavish deference, or you do whatever you can to destroy the insubordinate. Totaler Krieg! And of course it helps if the opposition is weak, poorly-organized, and not as focussed and motivated as you are. The Israel lobby isn’t the only case, but it’s probably the most successful and the most important.