Imagine Bush sitting and wathcing India parade its nuclear capable missiles and the message it sends to others. I don't think Bush will take up that offer. Besides, I'm not sure the Secret Service is going to be keen on the POTUS sitting in open air as tanks and military vehicles pass by not too far away. I know India has a professional military but there is still a chance that some looney might inflitrate the parade and do something.
Not a good idea IMHO.
Wasn't Egyptian President Anwar Sadat assassinated during a military parade? Not a good precedent.
I think the Bush administration is walking a fine line between the Indians and Pakistanis. I don't think President Bush wants to be seen to tip more towards one side or the other. Maybe a lower level administration figure will be sent to New Delhi on Jan 26.