Even by the most conservative estimate, there was excessive firepower to do that since decades ago.
Rankings of world thermonuclear powers by megatons of firepower: 1. Russia - 1,273 megatons 2. United States - 570 megatons 3. China - 294 megatons (China has over half the nuclear firepower of the United States) 4. France - 55 megatons 5. Britain - 16 megatons References...
defence.pk
But MAD is always the hurdle, that's why surmounting this is a top investment priority for all three players in the game. On the strategic defence side there are land-based mid-course interception and ASAT with KKV tech, its sea-based versions (Dual-band Type 055 destroyers), as well as massive orbital infrastructure comprised of various constellations like infra-red, GaoFen, comms, Beidou and such.
On the offensive side ICBM/SLBM with MIRV is the current pillarstone, while FOBS+HGV is a very attractive option to explore, I guess it's what this test is about. There are alot of liquid-fueled heavy-lifters at disposal all very matured/reliable, sending heavy orbital vehicles up is easy. It can supplement the relatively short range of HGV which typically can only ramjet for ~1200 seconds. This combo gives commanding officers far more flexibility in choosing the best attack route by avoiding heavily guarded regions such as North Pole. Such test can further prep readiness for orbital bombardment system, i.e. no longer fractional, by keeping those HGV in orbits, such option should be on the table.