> Roundup (aka glyphosate) seems to be pretty safe https://en.wikipedia.org/wiki/Glyphosate#Glyphosate_alone

If you're concerned about the safety of glyphosate formulations you may be interested to learn that the testing and regulatory process appears to have been captured. [0] [1]

> Why would there be?

Are you asking why there would be a difference between a topical application that could be rinsed off and a substance that is produced by the plant and is inside the plant material itself?

> But the scope and extent of the effects are not known.

Indeed, this is why the precautionary principle is at play here.

> Glyphosate and bt have both been thoroughly studied.

They've been studied enough to suggest that they are potentially hazardous depending on the dose and context.

> With your "precautionary principle" we'd all be not eating chocolate right now if it was first used as a pesticide (chocolate kills dogs, so if dogs were somehow a pest, it can be used as a pesticide against them).

That's not a valid interpretation of the precautionary principle.

> So mutations are intrinsically bad? In other words, if there were some way to stop naturally occurring mutations globally, you'd support it?

I haven't suggested that, of course mutations are not "bad", they just are. I was responding to your placement of GE products in opposition to mutations. No, I wouldn't stop evolution if I could, but that's interesting and I wonder if a population with no mutations would have significantly lower cancer rates. Its an interesting thought experiment.

> It's a problem, but the alternative (not using any GMO/herbicide) is worst, since the weeds will still be growing out of control. At least if you used GMO/herbicide you have a few decades of weed-free growth.

There are other ways to control competitor organisms besides herbicide and there are people who use conventional herbicide that don't use GMOs (and so they don't use as much herbicide). Just so you know, most farmers are not letting weeds grow out of control on their fields :)

> This is totally orthogonal to the discussion of GMOs. If you're worried about pesticide/herbicide run-off from farms, then you'd want to regulate it directly, rather than trying to regulate it by proxy by limiting access to technology that allows for greater pesticide/herbicide use.

Are you suggesting that it would be better to place limits on how much / how often herbicide could be applied to a field? Perhaps so but I'm not convinced that the laws in this case could be finely tuned enough to achieve the effect without creating a rule that was either too strict or too lenient (or perhaps both at once) for a large percentage of farmers. Without a selective herbicide/crop system, farmers have to be careful about when and how much herbicide they apply, lest they kill their own crops. With a selective herbicide/crop system, they can just cover the field in herbicide, resulting in substantially greater application amounts. Your argument that application amounts could be specified by law leaves me unconvinced that the concern with the selective systems is misplaced.

> It's not like the threshold where herbicide levels tolerated by non-gmo crops is the same threshold that ecosystem damage occurs.

Its likely that ecosystem damage is unavoidable with agriculture and so we prefer a minimalist approach, rather than meeting some arbitrary threshold value (which could only be estimated on the basis of imperfect knowledge anyway).

> Not to mention, non-gmo crops can still have their herbicide resistance raised by selective breeding.

I know some farmers who would be very happy if the same level of herbicide resistance exhibited by GMO crops was available in a non-GMO product. I'm sure its possible, perhaps we will see this someday.

[0] https://www.baumhedlundlaw.com/assets/Monsanto%20Roundup%20p...

[1] https://www.baumhedlundlaw.com/toxic-tort-law/monsanto-round...