There's also the first filter of wanting the position in the first place. Not just believing that they could do a good job, but wanting to be the one governing a country that is in many ways ungovernable. Power always has its attraction, but at the moment the US president seems to have only the purpose of taking the blame.

You're being careful to say that you know it's possible to put people on mars, but you seem to be arguing that it's fundamentally impossible for them to stay there for the long terms. You seem to be suggesting that faster than light magic is more likely than us figuring out how to manufacture greenhouses on mars. Do you really believe that closed cycle life support is so massively difficult a task that finding new physics and building the starship enterprise is a better hope?

Yes, mars sucks if you have to go out on it without protection, and yes setting up a self sustaining colony would be difficult, dangerous and very expensive. I'm not suggesting that we do it all right this instant. But everything that is necessary for human life could be manufactured on mars, and the tools to maintain that capability could be built there too. The more manufacturing centres you set up, and the more diversity there is among them, the more robust it becomes - tools existing to repair or rebuild other tools, exactly the same way we maintain stuff over here on earth. I am well aware that it would represent a really vast quantity of machinery to achieve all this, but I still think it can be done.

Again, I'm not saying we do this anytime soon! In the short term we do need to figure out how to live on just one planet, but over the course of a century or more it makes sense to start work on a permanant human settlement somewhere off earth.

You do realise that there are some planets in our own solar system, right? The summary mentions them.. Colonies around other stars can wait for a long time, since we only need those to protect against really really huge disasters like supernovae or the sun going out. Those aren't going to happen for a VERY long time, so we can ignore other stars for now. What we need is self sustaining colonies off Earth, but near enough to be able to interact with Earth, hear Earth's messages, learn Earth's lessons. The threat we're guarding against is that of having a vast number of people stuck in a single biosphere, all complex unpredictable people, occasionally inventing new and dangerous things. A few decades ago, nuclear war seemed like the manifestation of that. We got past that hurdle with civilisation intact. How many more inventions like that will there be? How many times can we pass the test?

If the daily mail ran a headline claiming that two times three equalled six, I'd double check on my fingers before believing them.

This was a quite prominent issue during the London riots earlier this year. Even with arson and city-wide looting, and with the vehicles available, water cannons weren't used. The political effect of breaking a precedent and using water cannons in mainland england for the first time was considered too great, even when the alternative was to let parts of Croydon burn.

Blinding laser weapons are specifically mentioned in the Convention on Certain Conventional Weapons annex of the Geneva Conventions.

See: http://en.wikipedia.org/wiki/Protocol_on_Blinding_Laser_Weapons

And yes, it does make a specific distinction between temporary and permanant blindness, so this thing is almost certainly legal as far as this particular protocol goes.

I should point out though, that the UK police have never even resorted to using water cannons outside of Northern Ireland, and use of riot equipment is a very serious political issue here. Breaking out the doom rays on a crowd of protestors is not going to happen lightly, and if it did happen, it would not be brushed off or ignored afterwards.

Atmospheric pressure at surface level on Mars is about 1% of Earth's pressure at surface. There's not much to hear. It's not going to be totally silent, but sound will be extremely quiet and distorted.

SpaceX have had only a single successful commercial flight, and even then that was somebody being willing to take a risk on putting their payload onboard a testing flight. I'm happy to be hopeful, and I see no reason why they can't in time develop into a company with a record for reliability, but it's premature to say that they deliver stuff that works.

I don't think it could ever be possible to enforce such community-driven equivalents of regulation without ultimately reverting to a system backed by what a libertarian would call the threat of violence. I don't really see what would stop somebody from buying some land, refusing to buy property insurance, and building whatever they like based on the idea that "It's my property now, and you have no right to tell me what to do with it." This is one example of what I don't like about the libertarian ideal. It draws an unhelpful distinction between deliberately inflicted harm (which they rightly denounce as violence), and accidentally or indirectly inflicted harm (which usually seems to be ignored on the principle that it is either an acceptable loss or that the free market will deal with it).

What does the wall represent in this metaphor? What could possibly be worse for the economy than a completely uncontrolled and instantaneous breaking of obligations and established services? Even massively high inflation from being dropped as reserve currency would be only about equally bad.

You don't drop a girder in front of your train just so that you can avoid the girder ahead.

The US health care system used to have equipment, skills and facilities that enabled giving the best level of care in the world, this is true. The problem is that it was only marginally better than everybody else, while costing four times as much as the hippie-commie-socialist-euro health care services. The level of service was definitely not four times better.

Yes, China is attempting to slow its lending to the US, but it's a slow and messy process. They do not have the ability to just stop or change terms of lending.

They're still in the process of slowly (very slowly) dismantling their currency manipulation practices which have been devaluing the yuan against the dollar. The way it was done, and the only way it could have been done, was for the chinese government to exchange dollars and yuan at fixed prices, which inevitably meant buying a lot of dollars. Since they couldn't just have a load of dollars in cash lying around in a vault somewhere, they did have to invest it. and it had to be invested as dollars, not just converted back to some other currency first, as that would defeat the point.

A sudden change in lending from China would come at the cost of damaging their manufacturing and export industries. It's happening, but the government isn't stupid, so it's happening slowly enough for businesses to adapt and survive with minimal job loss.

An unbreakable debt limit isn't smoothly applying the brakes, it's dropping a girder on the track ahead of you. You don't try to slow a train in one instantaneous movement.

Yes, they look very different. That's as a result of their construction methods, which was what I was comparing. Skylab was built in one go on the ground and was launched in a single flight. The ISS was flown up in bits.

In terms of function, what actually matters, they were very similar in purpose. The ISS cost about 40 times as much, but definitely did not offer 40 times as much living space or power.

Reliability and maturity of life support tech was a lot better on the ISS, but I think it's fair to argue that construction method and launch vehicle didn't contribute to that.

The ISS is in a useless orbit, chosen mainly so that access from Baikonur would be possible. Moving components from the ISS orbit to a more sensible one would not quite require as much fuel as launching new ones, but given the extra hardware involved in dismantling, ferrying about and rebuilding... it would be cheaper to launch new stuff.

One other thing that should be remembered is that the ISS was partly an experiment in how to construct stuff from multiple modules to be assembled in space. The lesson learned was basically: don't do it. Skylab had approximately the same capabilities as the ISS, maybe a bit less power available, and fewer docking ports, but it was built, launched and operated on a total cost of less than a fourtieth of the cost of the ISS. If you've got the right launch vehicle, a space station does not have to be hugely expensive.