ideologically and politically, and of course morally, it would have been shattering for the US
militarily the US marine corps battalions were technically far superior to India's. However, they would have been fighting on unknown territory and against Indians who knew how to work with systems etc. that didn't work
They would have gone home in caskets, but seriously damaged india's war making ability. This would have been too late to save pakistan's army getting crushed.
Net result would have been anarchy with all of the sub-continent's military forces in shambles.
And the blame would have been completely put on the US. This would have been a political and moral disaster. The US would have had no moral standing to oppose the USSR.
Thank God it didn't happen.
Thank GOD it didn’t happen.
It would have accomplished....NOTHING.