Applying for MPP or MPA as a career change option

[strawflower]

I wanted to ask your opinion on the value of getting a MPP or MPA to eventually get a PhD position. I do not have any policy background (except one class during BS which I loved and did very well in). I have a B.S in mechanical engineering 3.34 GPA from a top engineering school. I was offered an fellowship to complete a masters in engineering as well but at a joint degree program in France - so technically I have 2 masters, one from a top American engineering school and another from a top French school. (one of the biggest reasons for taking this opportunity was to learn French since I thought it would be an additional asset -since I am fluent in Spanish and Bengali as well- for working in foreign policy or international affairs) I currently work in a large company in the oil industry as an engineer and have other work experiences but none directly related to policy. I have always wanted to go into public policy but as you can see other opportunities kept me from pursuing it before. Although I haven't re-taken the GRE, I did take it as a formality for my graduate work (therefore I had no real preparation) and got 680 verbal and 720 quant. I am fairly confident with a little preparation I could do the same or better.

Eventually I would like to be accepted in a doctoral program in order to become a professor or work in a think tank/NGO. Since I do not have any formal experience in research, I feel that I should pursue a masters and then eventually use it to get into a PhD program. What are my chances in making this happen? I assume that the MPP program would be better suited than the MPA, is this a correct assumption? And lastly, what are my chances in getting into a top program such as KSG or WWS with no policy background and in fact with a very different background than the norm (i.e. engineering)?

Thanks