I doubt political parties are much responsible in this. Politicians are simply too untrained and too stupid to run a country and manage its strategic and diplomatic interests. They are good at playing popularity based politics (which in essence is what democracy in our parts of the world is). They are master at understanding populist agenda with people but decisions to vacate heights, occupy them, fabricating treaties and policies are beyond their competence level and even they know it. These nuts and bolts are delegated to their principle secretaries etc sitting in PMO/Defence Ministry/EAM. Its these unnamed bureaucrats who run the real show.
Politicians in India are only worried about this much : How will these decisions look on their election front. Beyond that they neither care nor they are competent to even understand what the hell is happening. I mean, these folks distributes ministries like candies. I mean look at this : Rajnath Singh - Wikipedia
Road Ministry then CM of UP then Agriculture Minister then Defence Minister.
Do you think this is a resume of a defence expert? I doubt this guy can even tell smoothbore from a rifled gun. I also doubt he has any delusions about it. Career politicians are very pragmatic about their own interests.
They are faceheads. Real policies makers and breakers are bureaucrats. The UPSC selected b*******. And they are whom I call dabba-wallahs. It does not matter if Congress comes or BJP comes, on the matters of "national importance", these folks are responsible. And in India they have been doing a terrible job. Worse than terrible job.