If we reverse engineer the javelin and break all intellectual property rights, that will be the last american weapon system we will ever aquire. That would be penny wise and pound foolish. Either get these in small numbers with no ToT, and/or buy from someone else (Israel) who will give us ToT. If the sellers are not willing to part with their IP, then the buyers have an option not to buy. But it would be unethical to buy and then reverse engineer (steal) their IP.
Who India wants to buy from is upto India. What all the US is willing to sell is upto them. If we don't buy from them due to their unwillingness to part with IP, then we can exercise our option of buying from others. It's their loss. Stealing from them woulod be a short termm loss for the US and a long term loss for India. It is not just complete weapon systems that India will need to buy from the US in future - many components of most western equipment come from the US, even for the european ones.
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