In order to understand the present US foreign policy we need to understand the various global political agendas of various groups in US. Depending on the administration one group or the other or a combination these groups will be in power.
Agenda-1: Neo-Con Agenda
Agenda-2: Conservative Agenda
Agenda-3: Realistic Agenda
Agenda-4: Puritan Agenda
I have always noticed US administration following Agenda-1 or Agenda-2 or Agenda-1+2 or Agenda-2+3 only. Agenda-4 is purely academic. Even Clinton administration followed Agenda-3+2, it was not purely Agenda-3. I have also noticed India gained maximum by making deals with US administration that follows Agenda-1 or Agenda-2. Other US administrations (i.e mainly Agenda-3 administrations) generally sermon India rather than helping India with anything worth mentioning.
It is always better for India to evaluate the behavior of all the groups before getting in to any deals with US. Most of the times US gives guarantees only orally which means they are valid only for that administration, while they extract perpetual guarantees from the other nations. The best example is India-US nuclear deal. The conditions attached by the US congress may be considered as advisory by the present Bush administration but the next president of the US most certainly will act differently.