Well..inernal rebels will fade away with time as the Indian Union gets stronger and there is a better economy to help the people.
The main problem for us is : China, Pakistan, Bangladesh
China: Peace is there, slowly things are getting back to normal. China would not intervene from the opposite side in any war that India has. It has stated that China wants good ties with India. I am 100% sure that give another 20-30 years, and China problem would be resolved. Its slow, but there is an actual movement, substantial movement.
Pakistan: No need to say. They have enough things on their plate. They are no match militarily or economically.
Bangladesh: TOOOO small economically or militarily. What we gain is their gas and transit rights. And Bangladesh is in turmoil. The only way apart from sea to Bangladesh is through India. So Bang. remains isolated. India could foster good relations slowly, or have a coup there. Its in shambles anyway.
No other threat to India. Time is our friend. With Time, our country has prospered. In 15 years we have accomplished SO much. The country left its socialistic attitude for capitalistic attitude in ''91. Now look at the country. Give another 15 years, and we'd be all set to see India among the top 5