"So much preparation had gone into the diplomatic date that a US-India dalliance at the end of it was a foregone conclusion."
Does foregone conclusion mean that a US-India dalliance was not conceivable?
The issue was with the connotation of the word 'dalliance' instead of 'foregone conclusion'. As clarified by David below, dalliance here means a diplomatic 'relationship' as opposed to the word's denotation: The deliberate act of delaying and playing instead of working.
Thanks for the help!