It seems inevitable that intractable problems will generate utterly unrealistic "solutions" from onlookers, but this conflict seems to be doing more than its share. This has to be right up there near the top:

If the United States and its allies want to combat the Islamic State jihadists (IS, formerly known as Isis) successfully, they should arrange a ceasefire between the forces of Syrian President Bashar al-Assad and the non-IS Syrian opposition.
If we're going to presume omnipotence, why not just "arrange for" the ISIS guys to shoot themselves and/or each other, and have done with it?

Obviously Assad has no interest in a truce with "the non-ISIS opposition". His interest lies in annihilating the non-ISIS opposition, so he can pitch himself as the only alternative to ISIS. Why would Assad go ahead with a truce and focus on ISIS when he knows perfectly well that as soon as ISIS is out of the picture he'll be the next target? Makes no sense. Assad seems perfectly happy to have ISIS in the picture, as well he might be: as long as they're around, he's no longer the least attractive alternative.

The proposal is every bit as unrealistic on the other side. "The non-ISIS opposition” is anything but cohesive and unitary: you're talking about hundreds of divergent and deeply conflicted factions, from relative moderates to full blown Islamist loonies like al-Nusra, which is among the most obvious demonstrations that "non-ISIS" does not necessarily mean "moderate". Even the thought of trying to get all or even most of them to agree to or observe a truce is far beyond the bounds of absurdity.

So we propose to “arrange a truce” between those who haven’t the capacity to agree on a truce (or anything else) and those who have no reason whatsoever to want a truce, and we expect this to happen… why? Because we decided that it should be? Again, if we were omnipotent we’d have easier ways of solving the problem.

Another prevailing utterly unrealistic proposal goes back to the old “find the good guys and make them win” mantra, also known as “arm and fund the moderates, and guide them through war and politics”. The obvious questions about whether a proxy war is really an advisable strategy, whether a suitable proxy exists, and (most of all) what we propose to do when our proxy doesn’t win are generally not answered, or even acknowledged: it’s just assumed that there have to be good guys, that they will surely win if we support them, that they will of course willingly submit to our “guidance”, and that of course they would never ever dream of applying our money and resources to any purpose not approved by us.

Given the number of times we’ve been burned in that particular fire you’d think we’d know better than to stick our faces back into it… but I guess we’re slow learners.

And then of course there’s the old reliable proposal that America should “demand” that the GCC regimes stop being oppressive and do as we say, as if they give a rat’s ass about our demands, and as if they need to.

All of these “proposals” have one thing in common: they assume capacities that do not in fact exist. That makes them quite useless for any practical purpose, though they do provide us with a way to make an unrealistic suggestion and then accuse others of incompetence for not following it. Why anyone would want to do that is something I’ve not quite figured out. Different strokes, I guess…