You're right that my perspective is a very US-centric one - I can't really speak to what's appropriate for a country like France, since so much of their infrastructure is already nuclear. In general, I think any country that hasn't already sunk huge amounts of money into nuclear would be foolish to start doing so now, because that money could be spent better on other tech.
I'm unclear on why (a) it is an "either / or" with nuclear power to you
I wish it weren't, I wish we had a blank check to do whatever it takes to kill coal, but unfortunately that's not how the US government seems to be approaching things. There's a limited amount of money available for non-coal subsidies, and the nuclear industry is getting /far/ more than its share of it. A cynic would say that it's because the same energy tycoons who've been burning coal all this time are now having their lobbyists draw up proposals for nuclear plants in an effort to keep the government cheese flowing and their business model undisrupted for as long as possible. The problem is that businessmen and politicians are presenting (and funding, respectively) nuclear power like it's the central solution to our problems, when in reality it has a peripherally supporting role at best.
So that might explain where I'm coming from better - you thought I was arguing in favor of coal when I pointed out problems with nuclear, but really my concern is to combat the overly enthusiastic way that nuclear is being embraced over sustainable tech in the US.
and (b) why you think nuclear power has such a longer lead in time than renewable.
I guess it's just a function of the complexity of the technology, and perhaps the safety precautions necessary. A solar or wind farm can be set up and operating at peak production quite quickly, whereas building a nuclear reactor and getting it online is a very long-term proposition. I'm sure that the time could be shortened by eliminating or weakening safety and environmental red tape, but I'd hope we're all against that.
let's also clear up exactly what we mean by subsidies here. That money is primarily going into R&D.
Again, not in the US. Energy companies (most of whom are running coal plants) are seeking government funding for the construction and operation of nuclear plants. Maybe they have a position on it, but I've never heard environmental groups like Greenpeace object to funding nuclear R&D, just the building of new nuke plants.
If you are arguing in favor of solar power in place of nuclear, then you'll find no argument from me as far as you are able to provide solar power to me. But if you can't provide me enough power from renwables, then I want the shortfall made up in nuclear power until you can,
Engineers concerned with energy efficiency sometimes talk about the "low hanging fruit". Basically, we need to start by optimizing the things that provide the most optimization with the least cost, and then move on to whatever is the next "lowest hanging fruit". Right now, solar power during the day and wind power during wind is really, really low hanging fruit. When it's day, a solar plant really does provide almost free energy, and similarly for a wind farm when there's wind. Granted these technologies aren't the full solution, but they're very clearly the most effective place to start. Once we're getting as much energy as possible out of renewables, then it makes sense to look at how to optimize the remainder of our coal use, with nuclear or what-have-you. But until we've tackled that low hanging fruit, devoting so much resources to other optimizations is inefficient. And in some cases, it's being used as deliberate misdirection by business people to distract us from the sustainable solutions which can severely cripple their coal-based business model right now.