Thread by @james_acton32

Time for some hypersonic myth busting!

Given Russia's Avangard announcement was last week, I'm a bit late to the party on this (parental leave, vacation). But Steve Simon's @nytimes op-ed is a useful springboard. (1/n)

nytimes.com/2020/01/02/opi…

@nytimes I should add that Simon's piece is hardly unique for making some factual errors/misleading statements, and his policy instincts (arms control!) are right. I'm using his op-ed as a handy example, not trying to single him out. (2/n)

@nytimes It's true that the US homeland missile defenses couldn't defeat Russian gliders. But they can't defeat Russian ICBMs either and aren't designed to do so--because that task is impossible. (3/n)

@nytimes So, yes, Avangard threatens the United States, but it doesn't meaningfully increase an existing threat.

To put it bluntly, if I die in a nuclear war, I'm indifferent as to whether I'm killed by a warhead carried by Avangard or one carried by an ICBM. (4/n)

@nytimes Yes, in one way, Russia is beating the U.S.--but U.S. goals are more ambitious. Avangard is likely nuclear-only. By contrast, the U.S. is focusing on developing nonnuclear hypersonic weapons--a more challenging goal because the accuracy requirements are *much* greater. (5/n)

@nytimes Indeed, generally, the military benefits of gliders are overstated, or at least, not likely to be realized in the near future.

I'd quibble with the paragraph below in various ways.

(6/n)

@nytimes First, hypersonic gliders are not necessarily accurate or global in range. In fact, the first conventional or dual-use gliders (e.g. Russia's Kinzhal and China's DF-17) are all medium- or intermediate-range.
(7/n)

@nytimes Like Simon, I worry a lot about accurate conventionally armed gliders with a global range. But they're really difficult to develop and are unlikely to e deployed in the next decade or so.
(8/n)

@nytimes Second, area defenses (think defensive linemen) against gliders are likely infeasible. But, point defenses (think cornerbacks) may well be viable. In fact, point defenses against gliders are probably more viable than against ballistic missiles of the same range. (9/n)

@nytimes This all matters in assessing both the military implications gliders and the possibilities of control. Partly because of the variety of hypersonic weapons, I don't think a general treaty is feasible (especially a multilateral one), even if it would be desirable. (10/n)

@nytimes A modest first step would be to make intercontinental gliders (nuclear- or conventionally armed) accountable under a successor to New START. Realistically, this requires extending New START while the US and Russia negotiate the successor. (11/n)

@nytimes Anyway, if you've read this far, perhaps you may want to read more! Here are three pieces of mine.

Me in @washingtonpost on the overhyped exhibition of China's DF-17 missile. (12/n)

washingtonpost.com/opinions/2019/…

@nytimes @washingtonpost A plain language explainer on hypersonics. (13/n)

carnegieendowment.org/2018/04/02/hyp…

@nytimes @washingtonpost And, Silver Bullet?, my slightly dated but (I hope) still helpful comprehensive look at hypersonics. (14/14)

carnegieendowment.org/2013/09/03/sil…