Thread by @ArmsControlWonk

North Korea's new ICBM is much larger than the Hwasong-15 ICBM (~2 m in diameter). Here are two stills from the parade that help illustrate the difference.

The truck ("transporter-erector-launcher" or TEL) is new. In December, @kyodo_english reported that Kim "ordered the mass production of vehicles used for transporting and launching missiles including [ICBMs]" using imported parts. Looks like it worked.
english.kyodonews.net/news/2019/12/9…

@DaveSchmerler and I previously documented the expansion of the March 16 Factory for producing these vehicles.
sentinelandenterprise.com/2019/12/23/new…

The large diameter means the missile has a bundle of either two or (less likely) three RD250-like engines. (Each engine has a pair of combustion chambers fed from one turbo pump.) That's a lot of oomph -- plenty for multiple warheads.

This is exactly how I am thinking about the problem, but said more directly and clearly.

https://twitter.com/EllemanIISS/status/1314973061322506241?s=20

The point is that North Korea is clearly aimed at overwhelming the US missile defense system in Alaska. This is completely predictable because its much cheaper for North Korea to add warheads than for the US to add interceptors.

If each new North Korean ICBM can carry 3-4 warheads, we would need about 12-16 interceptors for each missile. (The GMD system salvo fires 4 interceptors at each warhead.) The last time the US bought 14 interceptors, it cost ... $1 billion.
archive.defense.gov/Transcripts/Tr…

So each one of these missiles that North Korea builds will cost the US about $1 billion to defend against. At that cost, I am pretty sure North Korea can add warheads faster than we can add interceptors.