I think Amos is refering to the point that the US started the Spanish-American War. Like the war against Tripoli, the Mexican war, the Civil War, the war of 1812, there is always a doubt as to who started the war. After all, the taking of a US ship by "pirates" was accepeed practice- we just would not pay ransom, and were held responsible for the lost value ( to Tripoli) when we burned it. The SA war was caused by the Hearst newspapers, after there was an accidental explosion aboard the Maine. The War of 1812 was caused by the US response to the British actions of "impressing" sailors that the British claimed were formerly their citizens, and the Mexican war was a land grab, of course.
And we will not discuss any of the wars caused by the Monroe Doctrine ( ie, our invasions of most of Central/South America
So much for "the United States started a war with a first-strike invasion for the first time in its history," : We have been doing it all along.