Now, let's see what the significance of the Zimmerman telegram is to your theory that the sinking of the Lusitania was engineered by Jewish interests to bring America into the war. We know, first of all, that nearly two years elapsed between the sinking of the Lusitania and the entry of America into the war (at least, the rest of us know that; I suspect you imagine it was only a couple of weeks), so it seems a little unlikely that there was a direct causal relationship. We know that the German government discontinued its Atlantic U-boat campaign later in 1915, and that tension between America and Germany decreased markedly as a result. We know that the Zimmerman telegram re-inflamed these tensions, as it contained an outright declaration that Germany was resuming unrestricted submarine warfare; there had been sinkings of American ships, one in a surprise attack, in the early months of 1917, and the official stamp conferred by the Zimmerman telegram removed any hope that Germany could pretend that these were accidents or aberrations. And, finally, the Zimmerman telegram made it clear that Germany had hostile intentions towards the United States homeland, and was prepared to assist a third party in actual invasion of US territory.
The final act was Zimmerman's public admission that the document was genuine. Once its authenticity was beyond doubt, American public opinion was solidly in favour of war.
Say what you like about morals - although, in fact, the morality of America's entry into WW1 was perfectly defensible by the standards of the time - but there is no coherent argument for any other cause of the declaration of war than deaths of American citizens at sea from illegal German attacks and Germany's declared intention of supporting a war of aggression against the USA.
Dave
