Essentially what it says in the title. It’s fairly established that the German military under Wilhelm II formulated several war plans for a US invasion to reduce the latter’s colonial/international influence. While the actual feasibility of Germany pulling off an invasion/occupation (or beating the US navy, a critical component of their plan) could seem null, what would’ve happened if the Reich, in an unwise fit of weltpolitik, did in fact attempt an invasion/attack on the US? What would’ve been the outcome of the war, and what implications would it have for the continental balance of powers, the US’ position in world affairs, and the possible development of a world war (if it’s not butterflied away totally or moved up by this development)?