I too would very much like there to be more scientific understanding underpinning government decisions. There is some in the UK - I've seen House of Lords reports examining the energy market for example and analysing the claims made of the benefits vs costs. I don't know how much of this actually goes into the decision making. It certainly isn't loudly talked about in press conferences.
The words "government" and "science" in the same sentence always remind me of a documentary I saw about the Star Wars weapons programme, made after it all went thud, they interviewed various people who were involved, including scientists and one who was at a presentation on laser development that was being pitched to a government funding committee. I can't remember the exact numbers or the units, but basically the presentation said "to successfully use the lasers, they need to be at 10 to the power of 16 (I can't spot a superscript option on here to do the scientific notation properly) and currently were are at 10 to the power of 8.
"Oh my gawd" said a committee member "We're half way there."
And I'd also say that we cannot make decisions based on ethics and principles alone, because to make it work in the real world, you need to include science and engineering. I do also find it frustrating that there appears to be an assumption that scientists are not ethical unless there is someone keeping check on them. Yes, some scientists have done unethical things, so has every group (dodgy builders, greedy bankers etc, etc - it is easy to tar everyone with the same brush). I think that what should be done, and at times is, is the situation of laying out the pros and cons of doing something - that incorporates the money, time and human costs and benefits. Building a dam would be a good example - how much will it cost to build? How long will it last? How many people will benefit? How many will lose their farms? Will it really work as well as the people who want to build it say it will? Is it OK to harm a few people to benefit many? Is there a totally different solution that will harm none but will cost more?
There is also a third part of government decisions as well as ethics and science - business. Whether it is simply the cost, or a company lobbying and promising economic growth and lots more jobs, it is very influential.
However the political system does seem to include a lot of snap decisions and reluctance to change minds later. You have to be seen to be decisive and a strong leader and saying "That is way too complex for me to answer now, I'll come back to you tomorrow after consulting a panel of experts" is not done. It should be, it isn't. (If it is and anyone can point me to examples I'd be really cheered up.
I too would like to see sound science in SF (well the bits that aren't totally made up....
) where it touches on the real world as I have learnt a lot of history from well researched historical fiction. As a scientist I find it throws me out of the narrative when something that to me is simple science is done incorrectly - momentum in weightlessness for example - but a great deal of SF is relying on <insert magic here> - will it ever really be economic for there to be interplanetary trade fleets and tourists? When you add the cost of heaving stuff out of the gravity well at current technology, no. If you do invent some <super space engine> then it becomes possible. However even with books with <insert magic here> when they include science at the level of current knowledge done inaccurately, I find that irritating.
I would also note that if the engineering makes it possible, then there will be interplanetary trade - after all look at the stuff that thunders round earth that could be made locally - clothes, plastic toys etc. Mankind finishes up in a weird world at times - international trade and what is traded was not carefully decided in one big analysed decision, it just evolved as a series of decisions, some ethical others definitely not.